Opto- and Macroelectronics

Home , Photovoltaic effect, Solar Frontier

Highlights in Microtechnology, 2020, Photovoltaic Devices Photovoltaic Devices EPFL EPFL N. Wyrsch – IMT IMT - PVLab

N. Wyrsch 1 Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • • • Applications overviewsApplications Brief history Photodiodes Photodiodes detectors & PV devices for energyscavenging PV power market PV technologies Fundamentals of Content – – – – – – Module technologyModule PV PV Multi limits performance and principle Physical of PV Basics Market technologies - junction devices junction photovoltaics photovoltaics (PV)

N. Wyrsch 2 Highlights in Microtechnology, 2020, Photovoltaic Devices Applications, history and motivation

N. Wyrsch 3 Highlights in Microtechnology, 2020, Photovoltaic Devices solar radiation.'solar of theeffects underelectron'On influenceBecquerel, E. light. solution conducting electricityanin placed electrodes of twoupmetal made cell electrolyticanwith laboratory) Becquerel’sCésar laboratoryhis father’s (in experimenting while 1839,atof ageeffect (in the 19)photovoltaic the discovered physicist, experimental the French Becquerel,Edmund Photovoltaic effect Comptes -- generation increased when exposed to exposed when increased generation Rendus 9, 561 . - Antoine - -

N. Wyrsch 4 Highlights in Microtechnology, 2020, Photovoltaic Devices 2020: 1970s PV : costs drivendown by 80%, allowing applicationsfor such as offshore navigation warning lights and horns 1963 1958 1954 1941 1922 : 1916 1905 1888 1883 1877 1839 : Brief history : : : : : : : : : World production. lighthouses, railroadcrossings, anduse remote whereutility the world'slargest array that at time. bySharp Japan installs 242a Viable US The New York Times forecasts that solar cells will eventually First First Einstein Experimental Albert Edward Description Observation Discovery lead a to source of "limitless energy of the sun". • • Vanguard space I satellite poweredby aPV array high silicon photovoltaic cell developed by Equivalent Approx - Einstein’s Einstein’s paperonthe photoelectric effect wide photovoltaic module silicon of solar cells produced Weston Weston receives first US patent "solarfor cell" winsNobel prize1904for paper on photoelectric effect - power silicon PV cell (achieving 6%) byBell Labs. of of photovoltaic byeffect Becquerel PV PV production > of thefirst solar cells made from selenium wafersby Charles of the of photovoltaic effect solid in selenium byW.G. Adams andR.E. Day . surface : surface: . Einstein’s proofof theory onphotoelectric effect byRobert Millikan annual 600 energy 120 km - watt PV PV wattarray on lighthouse,a 2 GW/year production of (area of(area Lake Ohl of 12 - Geneva!) 15 nuclear - grid connections are costly; too start of mass power power plants Fritts (with efficiency (withefficiency < 1%)

N. Wyrsch 5 Highlights in Microtechnology, 2020, Photovoltaic Devices • • Solar Solar cells Photodiodes Devices and Applications – – – – – – – – – – – ….. Bio valves) (optical modulators Spatial detectors Position Light (X, detectors Particle ( imagers panelFlat microsystems scavenging, Energy C (off grid) systems Standalone grid) (on market Power onsumer applicationsonsumer - chips sensors a - a Si:H , b , ) g )

N. Wyrsch 6 Highlights in Microtechnology, 2020, Photovoltaic Devices Building integration of photovoltaics

N. Wyrsch 7 Highlights in Microtechnology, 2020, Photovoltaic Devices Building integration of photovoltaics Integration with shadowing Integration partial

N. Wyrsch 8 Highlights in Microtechnology, 2020, Photovoltaic Devices Denmark, 61 MW 61Denmark, Tressere Agrivoltaic PV fields , France, 2.1 MW MW 2.1France, , “Big Panda”, Datong, China, 100 MW100 Datong,China,Panda”, “Big in China, province,Anhui Floating solar powersolar 40 station MW Bhadia Topaz 21 st 2.24 Solar Park, Park, Solar 550MW, 25 km L largest Farm rgest G W , CA, USA CA, , PV plantPV , PV plantPV 57 India km 2 2

N. Wyrsch 9 Highlights in Microtechnology, 2020, Photovoltaic Devices Solar energy potential (1 liter liter (1 of Toe • • • • World World ( Irradiation Yearly One 10’000 Yearly : Ton: – – Power > 16 (> Energy hour petrol oil primary World World solar x World World x equivalent GToe : > of of  sea 16 162 solar energy 10 energy ) TW energy kWh) level energy PWh irradiation on irradiation  irradiation on irradiation , full , 10 consumption (162x10 consumption MWh consumption sun 12 ): ): kW/m 1 kWh) Earth Earth (2019): surface surface 2   10 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Potential of PV electricity generation • • efficiency 18 worldthe powerwhole the could discs dark hitting Sunlight TW (averaged) electrical power for solar cells with 8% with cells for solar powerelectrical (averaged) TW covering the area of the black theof black dots!thecoveringarea http://www.ez2c.de/ml/solar_land_area/index.html (low) 11 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Basics of PV 12 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices 2) 1) : process 2 step PV device carrier collectioncarrier Separation Absorption of a a photoninof of electronof the - Physical principle - hole pair thanks to the internal electric field of of a field electric to the internalthanks pair hole semiconductor - + to create a free free to electron create a - hole pair hole diode and 13 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Solar spectra solarreachingradiation Earthabsorption bandsthe and due to atmosphere.duethe AM1.5 AM0 Black body6000 at K Typical sunlight. incidentabsorption and of sky scatteringclear Source Source PVCDROM 14 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Air mass a • • calibrated at this intensity.at calibrated usually are systems of PV Efficiencies direction. verticalthe and where atmosphere) Mass Air – – – – – – AM1.5G (Global), AM1.5G (Global), AM1.5D(Direct) AM1.5 radiation intensity AMx the vertical direction. AM1.5: angle of 45 is sun at the vertical direction AM1:solar spectrum earth on surface when the (outside of the atmosphere) AM0:solar spectrum a defines defines both the is the angle between the sun beam the sun beam is thebetween angle  : Attenuation (through the (through : Attenuation 100

AM mW

 /cm

1 ° . of the the of sun with respect to

cos spectrum spectrum the and 2

a 15 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Spectral change of illumination

2 Spectral irradiaton density [W/m nm Daily (and seasonal) changes spectral of irradiation density 0.0 0.5 1.0 1.5 2.0 • • • (dependent (dependent on the local climatic conditions) Yearly irradiation 800 (Switzerland): Maximumirradiation (normal surface): kW/m 1 Differences mostly in the visible part of the spectrum 400 600 Wavelength Wavelength [nm] 800 AM3 AM2 AM1.5 AM1 AM0 1000 - 1200 1200 kWh/m (data) (data) 2 2 /year 20 30 48 equinox, noon, AM1.5(central Europe, equatorAM1: space AM0: ° ° ° above above horizon) above horizonabove horizonabove 16 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices 0 Forbidden gap gap gap E g of variousof semiconductor material T=300 at K Ge 1.0 Si a-Ge:H Cu 2 S InP GaAs CdTe AlSb

a-Si:H 2.0

Cu 2 O Se GaP CdS 2.5 E [eV] g • • • • • High absorption coefficient absorption High semiconductots: Non coefficient absorption Low …): (Si. Ge, bandgap Indiret coefficient absorption High InP,..): (GaAs, bandgap Direct E E gap a fixed has semiconductor Every g is temperature temperature dependent.is - direct bandgap (dosordered (dosordered bandgapdirect g , 17 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Absorption process High band High gap band (e.g. a Photon energy in excess lostof toexcess in is bandgap energy Photon are notgap absorbed the than bandless energywithPhotons - + - Si) Low band Low gap (e.g. band thermalization + - m c - Si) 18 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices

Incident photons Spectral conversion efficiency Cu c c

Incident photons photons

Incident photons photons - - Si Si Ge 2 O

(crystalline Silicon), E Silicon), (crystalline (crystalline Germanium),E (crystalline

(Cupper oxide), E oxide),(Cupper

g = 2.1 eV (biggap)= 2.1 g = 1.12 eV (medium gap) = 1.12eV(medium

Une small part of the of part small Une absorbed

h

Almost all photon are photon Almostall absorbed h

Une big part of the photons are photons the of part big Une Absorbed; IR photons are not are photons IR Absorbed;

h

s g

28%

= 0.66 eV (small gap)(small = 0.66eV

40%

48%

photons are photons

• • Remarks: where or efficiency) the of conversionlimit (physical efficiencyconversion Spectral

h (E (

S f



 ·q) corresponds ·q) an to electrical current g / / q)corresponds an to electric potential

Energy

Energy f is the photon flux photonis the

content

the

(

solar

)(

spectrum

)

per

unit h

unit S

time

time 19 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices

Spectral conversion efficiency hs Spectral conversion efficiency

100

spectral conversion efficiencyconversionspectral

gap

0.5

g Ge under CIS

AM1.5 c-Si

E [eV] E

1.5

With materials: these2 With differentwith gaps: semiconductorsof 2 Combination GaAs / CdTe illumination

as a function of a function as a-Si:H

2.5

h s

3 >60%. >60%.

• • • gaps may increase gaps increase may Combination of semiconductors with different Optimum bandgap for each spectrum h – – S

Si(small E depends depends on semiconductor gap light spectrum

(large E

)

h S

Incidentphotons

High energy photons are absorbed

Low energyphotons are absorbed

20 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Shockley • • • Maximum for : 33.7%AM1.5 Maximum Considerations cell solar junction) (single of limit a efficiency Fundamental – – – Spectral Spectral loss (no absorption & thermalisation) Recombination (only radiative, recombination of free holes and electrons) Blackbody radiation (radiation loss, depends on solar temperature) cell - Queisser limit http://sbyrnes321.byethost11.com/sq.pdf Wikipedia 21 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Device operation 22 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Electron • p – – - n diode: crystalline crystalline solar cells process carriers’ collection by diffusion -

Crystalline hole pair separation

SiO

300

p sc

type

500

solar cell

diffusion

+ •

p-type a-SiC:H

n-type a-Si:H

SnO

intrinsic a-Si:H

Al or Ag

Glass

0.3

Si:H p

0.5 – – –

2 - i -

p n structure structure n

m amorphous) photodetectors (crystalline or amorphous solar cells carriers’ collection by drift

solar cell

drift

+ Delft University Delft M. Zeman , 23 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Band diagram

Energy [eV] cell solarSi Crystalline 0 n + E E V C Depth [μm] Depth p E F 300 p +

Energy [eV] a 0 p - Si:H E F Depth [nm] Depth p E E - i i V C - n solar cell solar 300 n Delft University Delft M. Zeman , 24 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices I parallel with parallel with current A a diode + current in source illumination Under = Solar cell diode = darkness: In L What is asolar cell: First Basic Basic equivalent circuit I D I I I L V V I - V (current V (current voltage) curve I I - R

I I approximation L





 V V





I Ideal Ideal equation diode delivered delivered to load a ! Power be can





  

exp(

)



  

   25 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Solar Analyses Analyses of I Power - I max cell I - I sc - P I V curve - V max - max V curve P max V oc V V I I I L L L I I I D D D I I V I R M I = Conditions Short I=0, I=0, V = V Conditions Open R dissipation on Ideal power M - I =V sc - , V=0 , circuit - circuit max /I oc max , 26 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Equivalent circuit of a p

R I

p L



Isc



 I

0 D

s R

 p

R I p

 R s

oc I R R

I V p s

 series resistance (must (must be small) series resistance parallel resistance (must be(must high) resistance parallel

 -

I n solar cell

 • • • •

   characterizes: Theresistance parallel shunt) (or The series resistance cells Approximately applicable thin to Strictly applicable to

exp( – – – – – – recombination. additional (withrespect to idealthe diode) the impurities in junctions the the leakage currents at thejunction periphery the resistance of thesemiconducting layers. interfaces ( the resistance of metal the the resistance of themetallic connections

nkT



) ohmic



  

 contacts);

V p - R



R n junction n junction s

IR characterizes

s - semiconductor - film film solar (c R - p Si). 27 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Current generation/dissipation Photovoltaics CD Photovoltaics - ROM 28 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Device performance limits 29 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Space chargeregion Depletion region= • diodeIdeal Ideal Ideal p Total depletionTotal – donor/acceptor states donor/acceptor region withionized fully space bulk neutral region and Quasi - n junction and junction formation Excited acceptor states Freeholes p - type Diffusion of holes

Depletion region electrons Diffusion of • • • • • Excited donorstates Very thin depletion Verydepletion thin region carriers Drift negligible process minority for p n Sharp interfaces - - Freeelectrons region region with region with n - type p»n n »p drift drift currents Diffusion currents = region : In depletionthe 30 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Thermal equilibrium diagram In thermal equilibrium: drift current current drift diffusion= equilibrium:current In thermal E p p - - type bulk regionbulk x - Diffusion p Depletion/space charge regioncharge Drift 0 Drift Diffusion x - - n n - bulk regionbulk n - type q f i x E E E E F c i v 31 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Diode equation (Shockley) • model) in the (diffusion darkI(V) Ideal characteristics L D n T: thetemperature absolute constant : k Boltzmannthe where with diode): (for p idealanequations thePoisson andtransport, continuity Solving p A p , , , L n D D n n : diffusion length of the minority carriers in the in p, carriers minorityof the length : diffusion : diffusion constants of the minority carriers p,carriers the the inconstants : diffusion of minority : the dopant densities: dopantthe

dark



   

  

exp

n n area theA: junction charge elementaryq: the

n i

2 : intrinsic carrier density carrier : intrinsic

   



   



  

    resp resp , region n , n region - n 32 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Empirical expression and ideality factor • • • • 2 wherethe is n Can replace be by  When generation and recombination in the depletion region is not neglected: theoretical maximum of empirical This expression is an important basis for the calculation the of the minimum saturation current I Saturation current I ( recombination current is dominant)

I idealityfactor

dark



 0

. replaced by a more simple empirical expression replaced more empirical where bysimple a

     



dark

exp

10 V oc gap, carrier lifetimes, doping concentrations, applied voltage, etc. voltage, appliedconcentrations,dopinglifetimes, gap, carrier on thedepends whichto recombination,due the term Additional

     

 , et FF

exp

T which which varies between (ideal 1 case) and

     

     

exp

   

 0

1 is is given by:

 h

     



   



     



   

exp



   

     





  



     



     







  

      33 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Superposition principle I L - I max I - I sc - V Dark max Maximum power Maximum V Illuminated oc V • current photogenerated of the principle "Superposition" (in general not valid for for not valid general (in conditions a p for valid Principle I ( V ) =) I dark - I ( L n diode in idealinn diode V ) thin film diodes)thinfilm - I L 34 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Short Theoretical Theoretical maximumshort - under under illumination AM1.5 circuit current I - circuit circuit current  Experimental data sc • • • • Effect of the temperature: Effect of maximum Theoretical condition diode in short Ideal illuminated Assuming – – – – – – – decreases whenthe temperature increases). I semiconductor gap: solar spectrum norecombination. total collection of carriersthe light cell thickness sufficient forabsorbing all useful R sc s • • veryweakly temperature dependent ( = 0 0 = et q: elementary chargeelementaryq: time unitperpairs f : numberof : R p =  photogenerated I sc =I I sc L = I sc f q given given by : , with , - circuit circuit "electron - hole" E g 35 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Open (2) (2) where the valuestheI where Open AM1.5 illumination withapproximations:the AM1.5illumination - circuit voltage circuit - theoretical limit of limittheoretical circuit voltage V L are obtained from the Fig. 7.26, 7.26, Fig.thefrom obtainedare Voc as a function of the gap for afor gapof the function asa Kiess [ Kiess  Experimental data , 1995] 1995] , (3) (1) (1)



2 3 oc

g • • • • Temperature effect Temperature Limits V diode p expression of the ideal the empirical From gap depends on a supplied by cell directly Thevoltage – – – oc is a quasi is quasi a linear function the of gap Celsius forc temperature increases per(0,4% degree V efficiencies). cells working withlight concentration (higher V E oc oc g /q /q is anupper bound for

V decreases almost linearly whenthe increases if I



   -

1 Si).

1 , E

 g

10 L

2 3 increases





  

 V

E  oc

g : advantage of - n 36 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Fill - - factor factor and cell power I max I - I sc - V max P Maximumpower max = V FF oc I sc V V oc • powerpoint) maximum is power (maximum the cell output where I Fill - factor FF defined factor defined FF as m

FF , V , m

 are are the current and voltage when

m 37 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Fill semi for two values of the ideality for values twothe of ideality factor n an and for AM1.5 - empirical empirical value of Fill - factor factor FF illumination. illumination. - factor function a FF as the of gap  Experimental data • • • Temperature effect: Temperature quality solar For a cell: cell quality! of sensitive the solar indication a is veryFF for valid with diode). voltage of only is a the open function FF – – – temperature). temperature (due to changethe of FF decreases withan increase theof 0.8 FF < 0.85(c< 0.7 < FF ( < 0.8

v V

FF v oc oc

 (in the diffusion of the diffusion model (in the p >10, >10, n:



 a

/ - ideality

q Si:H

v -

 Si)

 )



. factor

 - circuit circuit V oc with - n 38 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Efficiency maximum "theoretical" limit under under illumination AM1.5 h as a function function a as gap of  Experimental data E g • • • h Practically and (second step) The total solar cell efficiency is givenby: with The efficiency h = p /n I h

h h sc P being efficiency the the of carrierseparation

h s max

 [mA/cm

/ the spectral conversion efficiency. 

 =

p P

/ I max

n m

    V 2 h

E ] m P

V V

g is is defined as: inc

oc = FF =

/ oc

q [V] FF [V] / 100[

    I sc V oc mW /cm 2 ] 39 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices

100% 75% 25% 50%

14% 12%

6% Efficiency dependences

0 h

rel

0,5

Intensity:mW/cm 100 50

T =25 T

Poly

1,5

Mono

100

T[°C]

Sun

• • Effect of Effect the light intensity of Effect temperature – – – – – injection). valid for temperature, diffusion model nomore intensity (loss in loss in light intensity (I materials. bandgap Decrease is less important forhigh Fora Forc h h decreases at high values theof decreases witha decrease theof - - Si Si : Si Si : R h p ). h h  decreases 0.4 by decreases by0.2 diodemodel underhigh L /I R 0 s ration of , increase , of the V oc - - 0.5 0.3 , and , %/˚C %/˚C 40 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Quantum efficiency or front deador frontlayer diodes or insufficientlythick PVCDROM - - - + + + 41 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Multi - junction devices 42 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • Increase Maximum Maximum Multi – – – – – – Maximum Maximum Maximum Maximum Shokley Decreasing Increasing - junction efficiency - Queisser theoretical efficiency efficiency efficiency spectral conversion conversion spectral current limit by ( for for triple for 42% tandem: for single reduction cell efficiency for for single spectrum depends component Optimal - junction efficiency - junction of of Joule efficiency choic cell on light light on ( solar materials : 33.7% of of : 49% Si: 29.4% Si: losses spectrum )

Bottom cell bandgap (eV) )

2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6

0.6

4 Terminal (no constraint on (no constraint current matching)

0 5 10 15 20 25 30 35 40

0.8

1.0

Top cell bandgap(eV) Top cell

1.2

1.4

1.6

1.8

2.0

2.2

2.4 43 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Monolithic tandem n p n + + + compared compared four terminal to devices Current matching required, narrower region high of efficiency Two device terminal

E bottom [eV] g

2,50

2,25

2,00

1,75

1,50

1,25

1,00

0,75

0,50

0,50 Map of Mapof max. efficiency (AM1.5)

0,75

0 0,04325 0,08650 0,1298 0,1730 0,2163 0,2595 0,3028 0,3460

1,00

1,25

top [eV]

1,50

1,75

2,00

2,25

2,50 44 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Tandem equivalent circuit

top top cell

bottom bottom cell

I [mA/cm2]

0.5

Simple Simple cell (single junction)(single

V [V] V

Tandem cell Tandem

1.5

L and tandemand typical I ( V ) curves a - Si:H • • • of a singleof a cells Tandem cell: Tandem cell: “Bottom” cell: “Top” – – – – V I V I sc = oc ( I @ min @ min ( - ) = ) = I junction = top V V = oc,top top I I top bot ( I I ) + sc,top I = + bot I V top V = oc,bot , bot I ( sc,bot I V bot ( I top ) ( V ) ) bot ) 45 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV technologies 46 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • Bulk technologies:Bulk Others, emerging technologies Others, emerging Thin PV technologies – – – – – – – – – – – – … Perovskite Organic polymers cells, “ Dye cells, ( CIS Indium Gallium CIGS (Cupper CdTe Amorphous GaAs Ribbon silicon silicon Polycrystalline Monocrystalline silicon - film technologies:film Cupper (Cadmium (Cadmium telluride) (III - V, space space V, based Graetzel silicon, micro silicon, Indium Indium application, application, concentrators), ” Diselenide - / nano Diselenide , - Cupper crystalline Indium Indium ) silicon, silicon, InP Sulfide micromorph (space (space application) ) 47 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Conversion efficiency vs.time Commercial cells exhibit efficiencies reduced by 20 byefficienciesreduced exhibit cells Commercial https ://www.nrel.gov/pv/cell - 60% - efficiency.html 48 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Availability of various materials for PV Availability of various materials 1 in ton of earth crust Germanium 7 g 277.2kg Silicon 50 kg 50 Iron Arsenic 5 g Total:1 ton Gallium Sulfur 520 g 520 15 g 15 Phosphorus 1.18 kg 1.18 Indium Cadmium 0.1 g 0.1 0.15g Tellurium 2 mg Cupper Selenium 70 g 70 90 mg 90 49 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • "Float Czochralski Poly Poly "Multi Crystalline silicon materials – – – – – – – – – – – R of or a by recrystallization Deposited by CVD mostly Material used solar for polycrystalline material withgrains large used Rarely for solar withgrains material veryPolycrystalline large only Used veryefficiency for high cells costs Very high quality Very high high with verydiffusion length for Standard material c Quality material with high diffusion carrier length (high at lifetime) moderate costs - - esearch esearch crystalline silicon (thin silicon crystalline (bulk) silicon crystalline - - crystalline zone" (FZ) (FZ) silicon zone" (CZ) silicon (CZ) activities, activities, " silicon small small cells, cells, (could be replaced by + quasi mono) - Si solar Si solar cells PV production - film) cells cells (but decreasing) - Si:H 50 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices c - Si standard technology Solar Solar grade Si 1. I ngot 2. Wafering Screen printed solar cells solar printed Screen 3. fabrication Cell 4. 4. Module 5. 5. PVCDROM 51 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • PERC cell PERC cell Limitation Limitation of contact Advanced c (passivated emitter emitter (passivated rear and contact), market newstandard - Si between technology Si and Si and metal contact contact ( less recombination ) 52 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices High efficiency c • with rear locally diffused) cell locallyrear with PERLemitter UNSW (passivated – 25.0% 25.0% efficiency - Si cells • (IBC : interdigitated back contacted) back : (IBC interdigitated Sunpower – 25.2 % % efficiency back back contact solar contact cells 53 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • Thermal coefficient: 0.2Thermal Highest efficiencylabBest structure: HJT Si heterojunctionSi cell (HJT cell) – – ITO (TCO) transparent transparent contact (TCO)ITO (~ a - Si intrinsic Si intrinsic layers 5 (~ nm) as super 10 10 nm) on the front and a efficiency for for c (Kaneka, IBC structure): structure): IBC (Kaneka, - - Si 0.25%/ cells - Si n+ contact Si n+ contact layer (~ nm) on the 15 rear. ° ! C for for C - V passivation passivation layers, as well as a oc , 0.25 26.7%, - 0.3%/ V oc ° C > 700 mV > 700 for for eff. (lower - Si p+ emitter Si emitter p+ than that of of thatthanc layer - Si!) 54 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices c - Si cell architectures • • • • Cells SHJ: Totally PERT: Cell PERC Silicon with : D P Passivated assivated Emitter assivated Emitter Rear iffused iffused passivating HeteroJunction Emitter contacts Rear 55 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • Large influence on Large influence Lower for standard Si Usual Depends Temperature values of values of up to 0.5 values for values for on technology cells thin energy coefficients Haschke et10.1039/c7ee00286f al., Haschke - film film technologies %/ production ° C for for P max 56 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices T hin - film film technologies 57 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV with thin film Si 58 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices a Absorption coefficient [1/cm] 10 - 10 10 10 10 10 10 10 Si:Hoptical absorption 5 -1 1 2 3 4 6 0 2.48 0.5 defects Subbandgap 1.24 Wavelength[micrometers] 1.0 Photon energyPhoton[eV] 0.83 1.5 0.62 2.0 c c Si a-SiC:H p-type a-Si:H a-SiGe:H 0.50 2.5 0.41 3.0 • • • • • Deposited gap bandOptical coefficient Absorption Alloy semiconductor (disordered) Amorphous – – – – – – a Depends Tunable energy Thin film (about micron) 1 absorbs 90% of usable solar In visible part spectrum of 70x higher than c « - • • non Si:H based materials basedSi:H materials alloys with Ge C - direct increases decreases H for H for at onH content low semiconductor defect E temperature g E g passivation » (≈200 ° C) by PEby C) - Si - CVD 59 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices 0.2 200Å 100Å - 0.4 µm 0.4 p - i - n solar cell Transparent Conductive Oxide Glass Glass superstrate Anti - Intrinsic a Intrinsic reflection coating reflection Back Back contact p n - - type type - Si:H - +  • • • • Light Light trapping scheme Opticallythick diode Electrically thin diode (“ Light enters the p cell through the semiconductors p     – – –  – - window window layer”) i - n structure necessary for disordered n structure necessaryfor disordered Minimal maximum absorption of light minimal recombination in i High electrical Higher Minimization The intrinsic layer is theonly active layer. the Dopedlayers onlyserve electric for field build Dopedlayer are very defective (deadlayers) intrinsic intrinsic layer bandgap thickness of of field hole for ( processing p collection collection - layer - layer ( low path time) optical ( low - layer loss hole ) mobility - up through ) 60 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Back reflector reflector Back Light trapping for thin film silicon cells trapping film silicon Light for thin Glass p Front ZnO ZnO Front - ZnO ZnO i - n • • Back reflector Back (TCO) Rough transparent conductive oxides deposition deposition process Roughness depends on deposited by AP Tin Oxide(SnO temperature thickness and depends film on Roughness LP deposited by OxideZinc (ZnO) - CVD 2 - ) CVD 61 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • Triples Tandems – – – – – – – – – Multi a a a a a a a a a ( commercially ------Si:H Si:H / Si:H a / Si:H a / Si:H / Si:H a / SiC:H a / Si:H a / Si:H / Si:H a / m m m - c - - c - c - - junction device for higher efficiency SiGe:H a SiGe:H / Si:H SiGe:H SiGe:H SiGe:H / Si:H / - - - - Si:H / Si:H / Si:H (mircomorph) Si:H Si:H Si:H a / m available m m c - c c - m Si:H Si:H - - SiGe:H c - Ge:H Si:H SiGe:H SiGe:H - Si:H Si:H devices in red , but disappearing • Issues – – – – – – – – a Current matching, very thin top Current matching (thick bottom) a a a m m - - - - c c SiGe:H SiGe:H stability SiGe:H stability SiC:H & a SiGe:H stability - - Ge:H processing processing Si:H for for powerthe - SiGe:H SiGe:H stability market ) 62 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • Examples on steel:on modules flexible junction, UniSolar – – - - module module efficiency ~8% stable cell efficiency: 13.1%

(1.75(1.75 gap)gap) eV eV

(1.1(1.1eVeV gap)gap) monolithic triple monolithic • • • Advantages: IMT (EPFL)byIntroduced comprising Micromorph – – Higher efficiency Higherefficiency andstability Better usage of solar spectrum Tandem Tandem devices ~1.6 ~1.6 eV ~1.8 eV ~1.4 ~1.4 eV

2 Intensity [kW/m /µm]

2.5 2.5 2.5 2.5 2.5

1.5 1.5 1.5 1.5 1.5

0.5 0.5 0.5 0.5 0.5

0 0 0 0 0

2 2 2 2 2

1 1 1 1 1

400 400 400 400 400

a a a

- - -

Si Si Si

:H :H :H

600 600 600 600 600

µ µ µ

c c c

WavelengthWavelengthWavelength

- - -

Si Si Si

:H :H :H

800 800 800 800 800

1000 1000 1000 1000 1000

[nm][nm][nm]

1200 1200 1200 1200 1200

1400 1400 1400 1400 1400 63 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • • Best lab efficiency : efficiencylabBest of Bandgap p betweenHeterojunction Relatively high cost cost (up high Relatively modules in cells of interconnectionMonolithic substrates foil, PI,SS)(Mo flexibleon Deposition Cu(In,Ga)Se CuInSe : 1.0 eV, 1.15 eV for 1.0 for eVCu( 1.15eV, : 22.9% (Solar Frontier), Frontier), (Solar22.9% 2 - solar cells scaling, In) scaling, - type Cu( type InGa )Se 2 20.4% (EMPA on flexible substrate) on flexible (EMPA20.4% InGa and n and )Se - type 2 CdS 64 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • • • • Best lab efficiency =efficiency labBest of Bandgap p betweenHeterojunction Cd issue ( issue Cd costs competitive production,Large lecturenext also (see hardness radiationhighVery modules in cells of interconnectionMonolithic EMPA)by13.8% efficiency (spin polyimide),coated substrates possibleflexibleon Deposition CdTe CdTe CdTe is inert and non toxic) nonand is inert : 1.45eV 22.1% - type (First Solar)(First CdTe and n and - type CdS ) lower efficiency (best (best efficiencylower 65 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Emerging technologies 66 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Organic photodiode structure • Best lab efficiency = 12% in tandem 13.2% triple junction ( triplejunction 13.2% tandem 12%= in efficiency labBest Polymers 6 (2014)Polymers P. Kumaresan Heliatek et al., et ) 67 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • monolayer absorptionmonolayer tophotosynthesis)(similar from electrolyte replenishment transfer TiO to rapidelectron molecules, dyein Absorption byInvented excitation Photochemical Dye sensitized solar cells ( Prof. Grätzel  adsortion (EPFL) on scaffold ( of on scaffold Grätzel meso - ) ) porous TiO 2 electron collector andcollectorelectron cell) O’Regan , Nature (1991)Nature , 2 68 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • General General L Cristallographic BaTiO common Crystallographic A Perovskites . A. bigger Perovski 3 , PbZrO form than oxides Br 3 ABX , B 3 with ,…) form (CaTiO structure of structure of I 3 3 , cubic A,B named 3 , SrTiO : cations, : cations, cell various from 3 , Russian X : anion, anion, mineralogist • M. Green Green M. Nature al. at from gap Opticalband NIR to VIS NIR Photonics tunable (2014) 69 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • • • (EPFL) (EPFL) High Large free Lead Issues : of Cs ClAddition in or Best Best Perovskites – – – ( H ( CH / / P3HT Au Structure: FAPbI MAPbI 2 NCHNH materials efficiency interest 3 NH interest using stability c 3 3 PbI or FALI perovkites or MALI 2 PbI 3 , fo lead iodide perovskite iodide lead : Methylammonium for for c : 3 25.5% 25.5% (UNIST/EPFL) solar , usage of usage , of Pb, , ), ), Formamidinium - Si / PK tandems / Si PK tandems (best solar cells CH perovskite 3 NH ( cells l ab 3 PbI LeadIodide hole Lead developments 3 with / increase TiO Iodide conducting (CH much 2 / ITO / ITO / Glass 3 NH efficiency lower stability 3 ), PbI layer, pioneered efficiency 3 ) : Oxford 28%, PV) metal by M. contacts Greatzel 70 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • feasible integrationfeasible high 1.5< eV (ideallySipartner to flat flat contacts transparentfully needs: constraints) or thermal (no epitaxial Perovskite/Silicon monolithic tandem Si - efficiency, low efficiency, - cell (for coating)spin(for cell - cost cost E g < 2 eV) Werner, J. ( also Phys.Chem : Albrecht, EES(2016) . Lett . (2016) . 71 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Tandem > 32.8 % 4 Thin - terminal tandem devices World World record AsGa /HJT (c - Si) (on (on Si) 4 « Perovskites Record: 29.5% (Oxford PV) Potential » on on HJT(c for for ≥30 - Si) % 72 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Monolithic • • T • • • riplemonolithic:junction, Concentrated PV Concentrated Efficiency(AM1.5 Efficiency PV:Concentrated Efficiency Space cells, cell for concentrated PV Semiconducteurs >3 (AM1.5) : 38.8% (5 j, j, (5 : 38.8%(AM1.5) (Sharp) : 37.9%(AM1.5) junctions ) : 39.2% (6 j, : 39.2%(6 j, NREL) ) : 47.1% (6 j, j, (6 : 47.1% 44.4% at 30244.4% : III - V ( AsGa Soitec Spectrolab suns suns , GaInP ) (Sharp), ,…) ) www.sj www.rwe.com www.emcore.com www.spectrolab.com - solar.com 73 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Advantages / disadvantages Perovskites Organic Dyesensitized CrystallineSilicon, thinfilm CdTe CIS / CIGS GaAs nano Thin filmSilicon(amorphe, CrystallineSilicon, ribbon multicrystalline CrystallineSilicon, monocrystalline CrystallineSilicon, Technology - crystalline) Availabilityof materials ++ ++ ++ ++ ++ ++ -- -- + - - Material usage + + + + + + + - - - - Toxicity of materials ++ ++ ++ ++ ++ -- + ? - - - -- + Efficiency ( ( +(+) stability?) stability?) ++ ++ -- + + + + - (indium!) ++? ++? Cost +? -- -- + + ? - - - 74 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV power market 75 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Mature (commercial) technologies Potential modules Efficiency Dye Organic Organic sensited 10 2 - 6% % a - Si a Si - Si/ µc 5 18 Thin film - - 16% Si % CdTe CIGS CIGS Polyc Crystalline Si 15 25 - - 22 Si Mono Mono c Si % % - Si Concentration Efficiency space cells III 20 30 - V V based - - 30% 40% 76 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Yearly 1 GW 1 GW : PV production Peak power of of powera Peak nuclear power plant ! plant power Jäger - Waldau , 10.1051/ , epjpv /2021002 77 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Yearly • ≈ 40% of 40% of PV market installations in China! Jäger - Waldau , 10.1051/ , epjpv /2021002 78 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Cumulated PV installation Jäger - Waldau , 10.1051/ , epjpv /2021002 79 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Biggest markets ( 2020) IEA - PVPS 2021 Snapshot 80 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Biggest markets ( 2020) IEA - PVPS 2021 Snapshot 81 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV share in the electricity mix ( 2020) IEA - PVPS 2021 Snapshot 82 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Experience learning/ curves • • increasing (BOS) system of Balance production when >20% cumulated decrease costs role is play doubled ! in PV an price 83 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV Energy Costs • • PV (PPA PV is electricity the the – power cheapest already purchase way offered of of agreements producing in in sunny , electricity bids countries countries at < for long long for !! https://www.holocene term 0.02 0.02 energy $/ kWh kWh ! purchase - energy.com/solar ) - ppas - pricing/ 84 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV modules 85 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Module serial connection technologies Bulk technologies Thin • • (see tandem tandem devices)(see Module voltages theby sum of cell givenvoltage output Module Monolithic interconnection Monolithic - film output current given by the minimum current thecell bycurrent minimum outputgiven + Substrate Substrate (glass, polymer or isolated metal) +

0.6 V

for thin for 0.6 V

- film film cells 0.6 V

- -

Metall p TCO - i - n 86 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • Voltage Voltage mismatch I Missmatch V 1 V 2 V 1 +V 2 V I I I • 1 2 Current Current mismatch – – breakdown breakdown avoidto diodeBypass polarizationreverse in Non   - Hotspot Power dissipation illuminated cell possiblycell illuminated V 87 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Bypass diode Photovoltaics CD Photovoltaics - ROM 88 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • Protection against environment against Protection Key issue for long term performance term module for issue long Key Important cost factor of varietymaterials Large Encapsulation – – Glass Glass - - glass glass encapsulation back foil encapsulation 89 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Standard Modules should testing sustain 25 years of of outdoor conditions ! conditions IEC 61215 standard 61215IEC Source:TÜV 90 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • Increase Bifacial Bifacial Half Smartwire Replacement of Ag by( Cu Technology cells cell «bus bar» «bus for for (replacement of (replacement bar» «bus , light collection , collection light less Joule Joule improvement number loss cost from ( ( lower less reduction both Ag, current sides b at module better y wires ) ) (diffuse on back (diffuse light carrier collection), collection), up to 9 carrier ), less shading level (c - Si) side ) - 12! 91 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • REC alpha REC alpha «Best» commercial – – – – – 20 «smart Half Temperature Hétérojunction year - cells - wire warranty series » (no «bus bar») » (no«bus coeffcient Si cell 380 W 380 (P): (P): - 0.26 product %/ ° C 92 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV devices for energy scavenging 93 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Energy harvesting Heel Hand Shoe Push Airflow (Piezoelectric) Vibrations generator)(micro Vibration Thermoelectric Light Ambient Frequency Radio Ambient TemperatureVariation Noise Acoustic Source Energy strike buttons inserts generators 7 W/cm2 W/kg 30 μ 330 50 1 μ μ 200 800 4 60 100 100 1 μ μ 10 0.96μ 0.003μ Performance & DensityPower μ μ W/cm2 (humanmotion W/cm3 μ W/cm2 μ μ mW J/N W/cm2 W/cm3 W/cm2 W/cm3 (machines W/cm3 office)(illuminated W/cm2 W/cm3 100Db @ W/cm3 W/cm3 @ 75Db W/cm3 /cm2 (directsun) F. Yildiz — , , J of — kHz) Hz) Techn . . Studies 35(2009) 40 94 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Light Power [W/m2/µm] 1000 2000 3000 4000 5000 • • 0 300 Superior Superior c (to a - Si:H 400 spectrum 500 band band gap 600 Wavelength [nm] Wavelength Amorphous EQE - 700 Si) performance Si) performance in well and 800 adapted 900 Halogen Fluorescent HCI AM1.5G efficiency silicon 1000 1100 to to indoor 0.2 0.4 0.6 0.8 (a 0 1 low

- EQE Si:H) illumination spectrum cell Light Light source Metal halide Metal halide Fluorescent Fluorescent N. Wyrsch N. Wyrsch et MRS al. 2005 Halogen AM1.5G HCI Efficiency 23.0% 14.8% 10.4% 6.1% 95 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Low light illumination a Dye c Dye CIGS c c - - - - Si Si commercial Si Si commercial mono 2 mono commercial Si 1 mono commercial Si commercial sensitized sensitized 96 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Solar modules for micro  modules voltage High Microrobots Up to 180 V from from mm 3x3 to V180 Up 2 -

Output voltage [V] systems

200

150

100

800 mV/segment 800

Number of segments Number

100

First module generationmodule First Second module generationmodule Second

150

200

250 97 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices a - Si:Hphotodiodes & detectors 98 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Thin + -

film film Solar cells vsPhotodiodes

+ - conditions for for conditions a photodiode Operation h n A i n p

Current density • • • illuminated dark diodecharacteristic contact:blocking (external field assisted collection) assisted field (external Operation h I photo of theby collection given contacts) blocking with(device photoconductivity primary Using ph  = Ge 1 ( - generated carriers generated h a Voltage - I with Si:H ph in reverse conditions for for best conditionsreverse in h cells : quantum efficiency,: quantum ) a for conditions Operation solar cell linearity 99 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices

SR (-3V) Spectral sensitivity thick thick a spectral response of a typical 0.5

0.8

0.6

0.4

0.2

300 - Si:H Si:H p

400  a - Si:H spectral sensitivity match ! eyesensitivitymatch human sensitivityspectral Si:H a -

500 - Si:H photodiodes used e.g. for display illumination control illumination e.g.used for display photodiodesSi:H i

Visible Visible - n diode n diode (at



[nm]

600

700 - 3 3 V).

800 µm µm

900 for (a) daylight for daylight (a) and (b) vision night spectral sensitivity the of human eye 100 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • Large area imagers for radiography Extensively photons visible ( layer a scintillatorwith coupled Photodiodes TFT byarraysaddressed photodiodes2D Cs:I ) for conversion of ) of x for conversion used for for digital radiography - raysto 101 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Fluorescence detector, microfluidic A mounted. platform where microfluidic CE device is fluorescence detector, forming acompact microlens and anintegrated a Schematic crosssectional view of a - Si:H Si:H B fluorescence detector. view of integratedthe Optical micrograph the of top Kamei, Kamei, MRS2010 102 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Hybrid detector using microfluidics • • • Under diode Detection Microfluidic array development using at chips channel integrated filled and tests EPFL/CERN at tests and end with a liquid - Si:H Sensors & & Sensors 2010 Actuators et al., A. Mapelli scintillator 4.5 4.5 x mm 10 2 103 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices Vertical Integration of Detector Arrays • Technology known as known Technology – – – – Elevated Elevated diode Above IC technology Thin Thin - - Film Film CMOSon (TFC) Film ASIC on (TFA) • Benefits – – – No dead dead No area and circuit complexity trade No between off sensitivity High fill - factor, factor, sensitivity high

F r o n t e le c t r o d e

a -S i:H p h o t o d io d e la y e r

B a c k e le c t r o d e

Insulationlayer

C M O S c ir c u it 104 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • • • • light Visible Dynamic Range: Dynamic >60 dB (@600nm): 56 V/(µJcm2) (fixedNoise patterned noise Sensitivity Dark current as as low20 Pixels connect charge to integrators unpassivated Metal TFA imagers – – – 92% 92% fill factor 38.4 size, µm pitch 40µm 64x64pixels - i - p a p - Si:H diodes Si:H diodes deposited on chip pA /cm2 • • • X - raydetection 15 µm thick 15 thick µm a connected to active feedback amplifiers 48 pixels with 150 µm size and 380 µm pitch 4x4mm 2 ASIC - Si:H Si:H diode 105 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices PV ressources http://www.pveducation.org/pvcdrom 106 N. Wyrsch Highlights in Microtechnology, 2020, Photovoltaic Devices • • Books Other Bibliography – – – – – – – 2 Wales, of South University New Devices, Systems Applications and CD Photovoltaics: and A. Shah, A. Solar Shah, A. Wales Silicon Solar Cells: Advanced Principles and Practice, Wales South New Cells: Applications, Solar Technology Operating Principles, System and S.M.Sze,Semiconductor Devices nd Smets edition edition online : at systems . Solar Energy: The physics and engineering of photovoltaic conversion, technologies Thin , UIT Cambridge - film film cells silicon and http://www.pveducation.org/pvcdrom solar solar Ltd Ltd (free Kindle edition !) modules, modules, Springer cells , EPFL Press , 2020 , 2010 - M.A.Green ROM byROM C. , University New of South Honsberg M.Green and and S. Bowden, , University of 107 N. Wyrsch