DOCSLIB.ORG

OPTICAL PROPERTIES of GALLIUM PHOSPHIDE (Gap)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
OPTICAL PROPERTIES of GALLIUM PHOSPHIDE (Gap) ISSN: Journal of Natural Print - 2277 - 0593 Science, Engineering Online - 2315 - 7461 and Technology © FUNAAB 2014 OPTICAL PROPERTIES OF GALLIUM PHOSPHIDE (GaP) 1* J. O. AKINLAMI AND 1 O. A. OLATUNJI 1Department of Physics, Federal University of Agriculture, P.M.B 2240, Abeokuta *Corresponding author: [email protected], Tel: +23480343892950 ABSTRACT Optical properties of Gallium Phosphide (GaP) have been investigated by means of Kramers Kronig method. Optical properties such as refractive index, extinction coefficient, dielectric constant, transmit- tance, absorption coefficient, reflectance, reflection coefficient and optical conductivity are presented in the energy range 1.03 – 6.01eV. The calculated optical properties of GaP indicate promising device applications such as the design of optoelectronic devices, electronic and photonic devices. Key words: Complex Index of Refraction, Complex Dielectric Constant, Transmittance, Absorption Coefficient, Reflection Coefficient, Reflectance, Optical Conductivity, Semiconductor INTRODUCTION GaP and related compounds are important Wide–band–gap semiconductors have at- semiconductor materials that are used in a tracted a great deal of attention due to their variety of optoelectronic devices (Kish et al, strong potentials in light emitting diodes 1994, Hofler et al, 1998). In this work, optical (LEDs) operating in the blue-to-ultraviolet properties of Gallium Phosphide (GaP) have region. Gallium Phosphide GaP is a popular been investigated in the photon energy range semiconductor material and considered to 1.03–6.01eV. be a wide-band-gap semiconductor, making it a good candidate for room-temperature METHOD OF CALCULATION device applications. GaP has potential for Kramers-Kronig analysis of measured data ultraviolet, blue and blue-green detection obtained by Schubert (Schubert, 2004) was applications from 250nm to 500nm (Beck et used to obtain the optical properties of the al, 2002; Liu et al, 2002; Zhang et al, 2008). material in the study. The Reflection Coeffi- cient which measures the fractional ampli- GaP is among group III-V compounds tude of the reflected electromagnetic field is which has been extensively developed for given by (Fox, 2001) applications to optical devices, LEDs, and photo cells. It has been found to be im- n 1 ik portant for light emission devices in visible r n1 ik range (Hatami et al, 2006) and is one of the (1) most promising materials for development of solar cells (Epstein and Grove, 1965). where n is the refractive index and k is the J. Nat. Sci. Engr. & Tech. 2014, 13:18-27 18 J. O. AKINLAMI AND O. A. OLATUNJI extinction coefficient. 4k Kramers-Kronig relations is a mathematical (5) model that describe the existence of a fun- damental connection between the real and where k is the extinction coefficient and λ is imaginary part of the complex optical func- the wavelength. tions descriptive of the light-matter interac- tion phenomena, such as the dielectric func- The transmittance is obtained from the rela- tion or the index of refraction. The real and tion imaginary parts, which describe dispersive and absorptive phenomena, respectively, are R + T + A = 1 (6) not wholly independent, but are connected by a special form of the Hilbert transform, where R, T and A represent the reflectance, which are termed Kramers-Kronig rela- transmittance and absorbance respectively. tions. Kramers-Kronig analysis allows one The sum of these macroscopic quantities to calculate the energy dependence of both must equal unity since the incident radiant real and imaginary parts of a specimen’s flux at one wavelength is distributed totally light optical permittivity, together with oth- between reflected, transmitted and absorbed er optical properties such as the absorption intensity. The absorbance (A) is given by coefficient and reflectivity. Because of Kra- mers-Kronig relation, the energy depend- 1 A log ence of the real part of the refractive index R is related to the material absorption, de- (7) scribed by the imaginary part of the refrac- The optical response of a material can be tive index (also called the extinction coeffi- studied in terms of the optical conductivity cient). (σ) which is given by the relation (Sharma and Katyal, 2007) The Reflectance (R) is given by (Yu and Cardona, 1996) nc n12 k 2 4 (8) R n 12 k 2 (2) where c is the velocity of light, α is the ab- sorption coefficient and n is the refractive 2 2 index. It can be seen clearly that the optical E1 n k (3) conductivity directly depends on the absorp- tion coefficient and the refractive index of E 2nk the material. 2 (4) The absorption coefficient (α) can be calcu- RESULTS AND DISCUSSION lated using the equation (Pankove, 1971, The refractive index spectrum of GaP in the Swanepoel, 1983) energy range 1.03eV to 6.01eV is as shown in Figure 1. There is an increase in the re- fractive index in the energy range 1.20eV to J. Nat. Sci. Engr. & Tech. 2014, 13:18-27 19 OPTICAL PROPERTIES OF GALLIUM ... 3.65eV, with a peak value of 5.50 at 3.65eV as shown in Figure 1. 6 5 4 3 2 Refractive Index (n) Index Refractive 1 0 0 1 2 3 4 5 6 7 Photon Energy (eV) Figure 1: Refractive Index of Gallium Phosphide (GaP) The refractive index decreases afterwards in and Kumabe, 1979) this difference is sus- the energy range 3.65–6.01eV. This de- pected to have come from the experimental crease in refractive index indicates that GaP procedures taken in the other works. Two shows normal dispersion behaviour. Our peaks are observed at 3.65eV and 4.80eV, result for refractive index is higher than that reported by Nelson and Turner (3.44) they are mainly due to transition (Zhang (Nelson and Turner, 1968) and Matsumoto et al 2011). and Kumabe (3.62 and 4.5) (Matsumoto 4.5 4 3.5 3 2.5 2 1.5 1 Extinction Coefficient (k) Coefficient Extinction 0.5 0 0 1 2 3 4 5 6 7 -0.5 Photon Energy (eV) Figure 2: Extinction Coefficient of Gallium Phosphide (GaP) J. Nat. Sci. Engr. & Tech. 2014, 13:18-27 20 J. O. AKINLAMI AND O. A. OLATUNJI The extinction coefficient spectrum in the peaks are observed at 3.8 and 5.27eV, they energy range 1.03eV-6.01eV is as shown in Figure 2. There is an increase in extinction are mainly due to transition (Zhang et al; coefficient in the energy range 2.7 – 5.7eV 2011). as shown in figure 2. It has a peak value of 4.2 at 5.27eV and then decreases to a value Figure 3 shows the dielectric constant of of 2.3 at 6.01eV. The increase in extinction GaP. There is an increase in the real part of coefficient with increase in photon energy the dielectric constant of GaP in the energy in the energy range 2.7 – 5.7eV shows that range 1.1 – 3.61eV as shown in Figure 3. It the fraction of light lost due to scattering peaks at a value of 27.4 at 3.61eV. The in- and absorbance increases in this energy crease in dielectric constant with increase in range and the decrease in the extinction co- photon energy in the photon energy range efficient in the photon energy range 5.7 – 1.1 – 3.61eV shows that the loss factor in- 6.01eV shows that the fraction of light lost creases with increase in photon energy in this due to scattering and absorbance decreases energy range. The real part of the dielectric constant then decreases with increase in in this energy region. The extinction coeffi- cient is zero in the photon energy range photon energy in the photon energy range 1.03 – 2.7eV which means that GaP is 3.61 – 6.01eV with a minimum value of -12.5 transparent in this energy region. The peak at 5.34eV. This shows that the loss factor value of extinction coefficient indicates a decreases with increase in photon energy in good absorption in the energy range. Two this energy range. 30 25 20 15 Imaginary 10 part 5 0 Dielectric Constant 0 1 2 3 4 5 6 7 -5 -10 Real part -15 Photon Energy (eV) Figure 3: Dielectric Constant of Gallium Phosphide (GaP) J. Nat. Sci. Engr. & Tech. 2014, 13:18-27 21 OPTICAL PROPERTIES OF GALLIUM ... There is an increase in the imaginary part of with increase in photon energy in this energy the dielectric constant of GaP in the energy range. The imaginary part of the dielectric range 2.6 – 5.07eV as shown in figure 3. It constant then decreases in the energy range peaks at a value of 26.9 at 5.07eV. The in- 5.07 – 6.01eV which shows that the loss fac- crease in imaginary part of the complex die- tor decreases with increases in photon ener- lectric in the photon energy range 2.6 – gy in this energy range. 5.07eV shows that the loss factor increases 0.25 0.2 0.15 0.1 Transmittance (T) Transmittance 0.05 0 0 1 2 3 4 5 6 7 Photon Energy (eV) Figure 4: Transmittance of Gallium Phosphide (GaP) Figure 4 shows the transmittance of GaP. coefficient then drops to a value of 1.39 x The transmittance of GaP peaks at a value 108 m-1 at 6.01eV. This high value of the ab- of 0.20 (20%) at 4.63eV indicating a low sorption coefficient is typical for interband transparent material. With a maximum of absorption in semiconductors (Sturge, 0.20 for transmittance it means that GaP is 1962.). It is important to emphasize that not a good transmitter of electromagnetic there is no absorption in the energy range wave in this energy region because for a 1.03 – 2.6eV which is the energy range of good transmitter the transmittance is 60% bandgap of GaP.
Load more

Recommended publications
  • Supporting Information For: Solution Phase Synthesis of Indium Gallium Phosphide Alloy Nanowires Nikolay Kornienko , Desiré D
    Supporting Information for: Solution Phase Synthesis of Indium Gallium Phosphide Alloy Nanowires Nikolay Kornienko1, Desiré D. Whitmore1, Yi Yu1, Stephen R. Leone1,2,4, Peidong Yang*1,3,5,6 1Department of Chemistry, 2Department of Physics and 3Department of Materials Science Engineering, University of California, Berkeley 94720, United States 4Chemical Sciences Division and 5Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley CA 94720, United States 6Kavli Energy Nanosciences Institute, Berkeley, California 94720, United States * Correspondence to: [email protected] Table of Contents: Figure S1. TEM In/Ga growth seeds ............................................................................................................................. 2 Figure S2. TEM of InP and GaP NWs ............................................................................................................................. 2 Figure S3. Composition and diameter control ......................................................................................................... 3 Figure S4. XRD of InxGa1‐xP NWs .................................................................................................................................. 4 Figure S5. Electron diffraction of InxGa1‐xP NWs ................................................................................................... 5 Figure S6. Raman spectra of InP and GaP .................................................................................................................. 6
    [Show full text]
  • Arxiv:1010.1610V1 [Physics.Ins-Det] 8 Oct 2010 Ai Mouneyrac, David Emndtetm Osat O H Rpigadde- and Illumination
    Detrapping and retrapping of free carriers in nominally pure single crystal GaP, GaAs and 4H-SiC semiconductors under light illumination at cryogenic temperatures David Mouneyrac,1,2 John G. Hartnett,1 Jean-Michel Le Floch,1 Michael E. Tobar,1 Dominique Cros,2 Jerzy Krupka3∗ 1School of Physics, University of Western Australia 35 Stirling Hwy, Crawley 6009 WA Australia 2Xlim, UMR CNRS 6172, 123 av. Albert Thomas, 87060 Limoges Cedex - France 3Institute of Microelectronics and Optoelectronics Department of Electronics, Warsaw University of Technology, Warsaw, Poland (Dated: October 27, 2018) We report on extremely sensitive measurements of changes in the microwave properties of high purity non-intentionally-doped single-crystal semiconductor samples of gallium phosphide, gallium arsenide and 4H-silicon carbide when illuminated with light of different wavelengths at cryogenic temperatures. Whispering gallery modes were excited in the semiconductors whilst they were cooled on the coldfinger of a single-stage cryocooler and their frequencies and Q-factors measured under light and dark conditions. With these materials, the whispering gallery mode technique is able to resolve changes of a few parts per million in the permittivity and the microwave losses as compared with those measured in darkness. A phenomenological model is proposed to explain the observed changes, which result not from direct valence to conduction band transitions but from detrapping and retrapping of carriers from impurity/defect sites with ionization energies that lay in the semicon- ductor band gap. Detrapping and retrapping relaxation times have been evaluated from comparison with measured data. PACS numbers: 72.20.Jv 71.20.Nr 77.22.-d I.
    [Show full text]
  • Basic Light Emitting Diodes
    The following is for information purposes only and comes with no warranty. See http://www.bristolwatch.com/ Light Emitting Diodes Light Emitting Diodes are made from compound type semiconductor materials such as Gallium Arsenide (GaAs), Gallium Phosphide (GaP), Gallium Arsenide Phosphide (GaAsP), Silicon Carbide (SiC) or Gallium Indium Nitride (GaInN). The exact choice of the semiconductor material used will determine the overall wavelength of the photon light emissions and therefore the resulting color of the light emitted, as in the case of the visible light colored LEDs, (RED, AMBER, GREEN etc). Before a light emitting diode can "emit" any form of light it needs a current to flow through it, as it is a current dependent device. As the LED is to be connected in a forward bias condition across a power supply it should be Current Limited using a series resistor to protect it from excessive current flow. From the table above we can see that each LED has its own forward voltage drop across the PN junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current, typically for a forward current of 20mA. In most cases LEDs are operated from a low voltage DC supply, with a series resistor to limit the forward current to a suitable value from say 5mA for a simple LED indicator to 30mA or more where a high brightness light output is needed. Typical LED Characteristics Semiconductor Material Wavelength Color voltage at 20mA GaAs 850-940nm Infra-Red 1.2v GaAsP 630-660nm Red 1.8v GaAsP 605-620nm Amber 2.0v GaAsP:N 585-595nm Yellow 2.2v GaP 550-570nm Green 3.5v SiC 430-505nm Blue 3.6v GaInN 450nm White 4.0v 1 Multi-LEDs LEDs are available in a wide range of shapes, colors and various sizes with different light output intensities available, with the most common (and cheapest to produce) being the standard 5mm Red LED.
    [Show full text]
  • Nonlinear Properties of III-V Semiconductor Nanowaveguides
    Nonlinear Properties of III-V Semiconductor Nanowaveguides ELEONORA DE LUCA Doctoral Thesis in Physics School of Engineering Sciences KTH Royal Institute of Technology Stockholm, Sweden 2019 Akademisk avhandling som med tillstånd av Kungliga Tekniska högskolan fram- lägges till offentlig granskning för avläggande av teknologie doktorsexamen i fysik onsdag den 23 oktober 2019 klockan 10:00 i sal FA32, AlbaNova Universitetscent- rum, Kungliga Tekniska Högskolan, Roslagstullsbacken 21, Stockholm. TRITA-SCI-FOU 2019:45 • ISBN 978-91-7873-318-7 "O frati," dissi, "che per cento milia perigli siete giunti a l’occidente, a questa tanto picciola vigilia d’i nostri sensi ch’é del rimanente non vogliate negar l’esperïenza, di retro al sol, del mondo sanza gente. Considerate la vostra semenza: fatti non foste a viver come bruti, ma per seguir virtute e canoscenza". Dante Alighieri. Commedia. Inferno – Canto XXVI. "O brothers, who amid a hundred thousand Perils," I said, "have come unto the West, To this so inconsiderable vigil Which is remaining of your senses still, Be ye unwilling to deny the knowledge, Following the sun, of the unpeopled world. Consider ye the seed from which ye sprang; Ye were not made to live like unto brutes, But for pursuit of virtue and of knowledge" Dante Alighieri. Commedia. Inferno – Canto XXVI. Translated by Henry Wadsworth Longfellow. Abstract Nonlinear optics (NLO) plays a major role in the modern world: nonlin- ear optical phenomena have been observed in a wavelength range going from the deep infrared to the extreme ultraviolet, to THz radiation. The optical nonlinearities can be found in crystals, amorphous materials, polymers, liquid crystals, liquids, organic materials, and even gases and plasmas.
    [Show full text]
  • WP934SA/IYGD5V T-1 (3Mm) Tri-Level Circuit Board Indicator
    WP934SA/IYGD5V T-1 (3mm) Tri-Level Circuit Board Indicator DESCRIPTIONS PACKAGE DIMENSIONS The High Efficiency Red source color devices are LED1 : Red made with Gallium Arsenide Phosphide on Gallium LED2 : Yellow Phosphide Orange Light Emitting Diode LED3 : Green The Yellow source color devices are made with Gallium Arsenide Phosphide on Gallium Phosphide Yellow Light Emitting Diode The Green source color devices are made with Gallium Phosphide Green Light Emitting Diode Electrostatic discharge and power surge could damage the LEDs It is recommended to use a wrist band or anti-electrostatic glove when handling the LEDs All devices, equipments and machineries must be electrically grounded FEATURES Pre-trimmed leads for pc mounting Black case enhances contrast ratio High reliability life measured in years Housing UL rating: 94V-0 Housing material: Type 66 nylon 5V internal resistor RoHS compliant APPLICATIONS Notes: 1. All dimensions are in millimeters (inches). Status indicator 2. Tolerance is ±0.25(0.01") unless otherwise noted. 3. Lead spacing is measured where the leads emerge from the package. Illuminator 4. The specifications, characteristics and technical data described in the datasheet are subject to change without prior notice. Signage applications Decorative and entertainment lighting Commercial and residential architectural lighting ATTENTION Observe precautions for handling electrostatic discharge sensitive devices SELECTION GUIDE Iv (mcd) V = 5V [2] Viewing Angle [1] Emitting Color Part Number Lens Type (Material) Min. Typ. 2θ1/2 12 25 ■ High Efficiency Red Red Diffused 50° (GaAsP/GaP) *6 *14 7 15 WP934SA/IYGD5V ■ Yellow (GaAsP/GaP) Yellow Diffused 50° *7 *15 12 25 ■ Green (GaP) Green Diffused 50° *12 *25 Notes: 1.
    [Show full text]
  • LED) Materials and Challenges- a Brief Review
    6 IV April 2018 http://doi.org/10.22214/ijraset.2018.4723 International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 6.887 Volume 6 Issue IV, April 2018- Available at www.ijraset.com Different Types of in Light Emitting Diodes (LED) Materials and Challenges- A Brief Review BY Susan John1 1Dept Of Physics S. F. S College Nagpur 06, Maharashtra State. India I. INTRODUCTION LEDs are semiconductor devices, which produce light when current flows through them. It is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable current is applied electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light is determined by the energy band gap of the semiconductor. LEDs are typically very small. In order to improve the efficiency many researches in LEDs and its phosphor has been taking place. However still many technical challenges such as conversion losses, color control, current efficiency droop, color shift, system reliability as well as in light distribution, dimming, thermal management and driver power supply performances etc need to be met in order to achieve low cost and high efficiency. [1] Keywords: Glare, blue hazard and semiconductor. I. DIFFERENT TYPES OF LEDS MATERIALS USED: A. Gallium Arsenide (GaAs) emits infra-red light B. Gallium Arsenide Phosphide (GaAsP) emits red to infra-red, orange light C. Gallium Phosphide (GaP) emits red, yellow and green light D.
    [Show full text]
  • Gallium Phosphide Light Sources and Photocells
    136 PHILIPS TECHNICAL REVIEW VOLUME 26 Gallium phosphide light sources and photocells H. G. Grimmeiss, W. Kischio and H. Scholz 621.383 :546.681 '183 Preparation and doping of GaP The methods of analysis used by us have failed to Amongst semiconductors with a relatively large detect the presence of carbon, which interferes with energy (band) gap, gallium phosphide has aroused luminescence in GaP, and this implies that the samples interest for various reasons. For one thing, by reason must have a e concentration of less than 5 X 10-4 %. of its 2.25 eV band gap, it is suitable for making P-N In the undoped state these crystals only exhibit very diodes which in some cases emit light in the visible weak luminescence. range of the spectrum. Our first task was to prepare gallium phosphide of high purity since, as will be made clear below, the efficiency of GaP light sources is very much dependent on the purity of the starting material. GaP is prepared by allowing gallium to react with phosphine; an ample supply of the latter gas, in a very high state of purity, can be obtained by decomposition of aluminium phos- phide with water. The aluminium phosphide is pre- pared by reacting aluminium with phosphorus. A mixture of pure aluminium and red phosphorus in an atomic ratio of 1: 1.1 is placed in an iron crucible and ignited. The reaction is fairly violent: some of the phosphorus evaporates and escapes into the atmo- sphere, where it burns spontaneously (fig. J). The aluminium phosphide yielded by the reaction is a porous sintered substance, yellow in colour.
    [Show full text]
  • Gallium Nitride Phosphide Absorber for Silicon-Based Solar Power Researchers Achieve 3X Efficiency of Best Gallium Phosphide Solar Cell to Date
    Technology focus: Photovoltaics 71 Gallium nitride phosphide absorber for silicon-based solar power Researchers achieve 3x efficiency of best gallium phosphide solar cell to date. esearchers in the USA have been working on that conversion efficiencies up to 45% could be gallium nitride phosphide (GaNP) as an absorb- achieved from an AM1.5G solar spectrum with a III-V Ring material for solar power [S. Sukrittanon et material on silicon. al, Appl. Phys. Lett., vol107, p153901, 2015]. The aim Gallium phosphide is one contender for such a top cell of the team from University of California San Diego since it is near lattice matched (0.37% mismatch) and (UCSD) and Sandia National Laboratories is to create a has a suitable bandgap of 2.26eV. Unfortunately GaP suitable sub-cell to boost the performance of silicon- has an indirect bandgap, which makes for inefficient based photovoltaic power conversion. Theory suggests photon conversion to electric power. Figure 1. Cross-sections of GaP control and GaNP solar cells. Inset: x-ray diffraction (XRD) spectra. www.semiconductor-today.com semiconductorTODAY Compounds&AdvancedSilicon • Vol. 10 • Issue 10 • December 2015/January 2016 72 Technology focus: Photovoltaics With the addition of only 0.4% of nitrogen into GaP, giving GaNP, the bandgap becomes direct, shifting absorption coefficients from 102–103/cm towards 104/cm. Further, at a nitro- gen concentration of 2%, GaNP becomes lattice matched with silicon. The UCSD/Sandia researchers achieved effi- ciencies up to 7.9% without a window layer. The team comments: “This GaNP solar cell’s efficiency is 3x higher than the most effi- cient GaP solar cell to date and higher than other solar cells with similar direct bandgap (InGaP, GaAsP).” They add: “These perform- ance gains are expected to motivate further investiga- tion into the integration of GaNP into future dual- junction solar cells on sili- con substrate.” The solar cells were grown on GaP substrates by molecular beam epitaxy (MBE) at 570°C (Figure 1).
    [Show full text]
  • NHC-Supported Mixed Halohydrides of Aluminium and Related Studies
    NHC-supported mixed halohydrides of aluminium and related studies A thesis submitted towards the degree of Doctor of Philosophy Sean Geoffrey Alexander November 2011 Table of Contents Abstract .........................................................................................................................................iv Declaration .....................................................................................................................................v Acknowledgements .......................................................................................................................vi Chapter 1: General Introduction .................................................................................................1 1.1 Group 13 chemistry ........................................................................................................ 1 1.2 Trihydrides of aluminium and gallium........................................................................... 3 1.2.1 Background............................................................................................................. 3 1.2.2 The thermodynamics of alane and gallane ............................................................. 4 1.2.3 Structural trends in aluminium and gallium hydride complexes............................ 5 1.3 Lewis base adducts of alane and gallane........................................................................ 6 1.4 Aluminium and gallium trihalides.................................................................................
    [Show full text]
  • Synthesis Routes for Large Volumes of Nanoparticles
    27 Jun 2004 11:37 AR AR218-MR34-02.tex AR218-MR34-02.sgm LaTeX2e(2002/01/18) P1: FHD 10.1146/annurev.matsci.34.052803.090949 Annu. Rev. Mater. Res. 2004. 34:41–81 doi: 10.1146/annurev.matsci.34.052803.090949 Copyright c 2004 by Annual Reviews. All rights reserved SYNTHESIS ROUTES FOR LARGE VOLUMES OF NANOPARTICLES Ombretta Masala and Ram Seshadri Materials Department and Materials Research Laboratory, University of California, Santa Barbara, California 93106; email: [email protected], [email protected] Key Words inorganic materials, metals, semiconductors, oxides I Abstract This review focuses on the preparation of capped nanoparticles of inor- ganic materials, classified by composition. The materials described include elemental metals and metalloids (semiconductors), chalcogenide II–VI and IV–VI semiconduc- tors, III–V semiconductors, and oxides (both of simple- and multitransition metal). Although particular emphasis is placed on methods that yield large volumes of nanopar- ticles, recent novel methods that may not necessarily be scalable are also reviewed. The review makes apparent the richness of chemistry that has become routine to prac- titioners in the field; diverse inorganic systems with distinct chemistry require distinct methods of preparation. INTRODUCTION The possibility to prepare monodisperse inorganic nanoparticles of pure materials in the sub-20 nm size regime, associated with the capping of these particles by (typically) functionalized long-chain organic molecules, has thrown open an entire field of research. Inorganic nanoparticles are finding myriad uses, ranging from traditional ones, such as coloring agents (in stained glass windows) and catalysts, to more novel ones, such as magnetic drug delivery, hypothermic cancer therapy, contrast agents in magnetic resonance imaging, magnetic and fluorescent tags in biology, solar photovoltaics, nano bar codes, and emission control in diesel vehicles.
    [Show full text]
  • Download : 0150117.Pdf
    Print ISSN: 0974-2115 www.jchps.com Journal of Chemical and Pharmaceutical Sciences Comparison GaP nanocrystal pure and doped with three atoms of Indium: Density functional theory study Huda M. Jawad* Department of Physics, College of Science, University of Al-Mustansiriyah, Baghdad, Iraq *Corresponding author: E-Mail: [email protected] ABSTRACT Ab initio restricted Hartree-Fock method coupled with the density functional theory method is used to determine the electronic structure and physical properties of pure Galluim phosphide (GaP) nanocrystal and mixed Galluim phosphide (GaP) nanocrystal with three atoms Indium (In) have been studied within the framework of Density functional theory using diamondoid structure, begin Diamantane, Tetramantane, Hexamantane and Octamantane, depened on simulation electronic structure of GaP nanocrystal. In order to full investigate the substitution of Ga by in on structural, gap energy, charge distribution, density of states, tetrahedral angle, dihedral angle, bond length. The results of electronic structure calculations are compared to the same size gallium and phosphide nanocrystals. The comparison reveals that the energy gap of the two kinds of nanocrystals. With remarkable dependence on the shape of the molecule or nanocrystal. The result show the energy gap decreases as a function of the total number of Ga and P atoms in most of the investigated range. Three atoms of Indium (In) to diamandoids GaP the effect of Indium shows a clear convergence in HOMO and LUMO levels. And effect of Indium shows in increased energy gap of GaInP diamantine. KEY WORDS: Diamondoids, Galluim phosphide (GaP), nanocrystal, density functional theory (DFT). 1. INTRODUCTION During last year's many efforts have been carried out to increase the efficiency in Diamondoids due to their role in nanotechnology.
    [Show full text]
  • High Purity Tri-Methyl Gallium (99.999%)
    HIGH PURITY TRI-METHYL GALLIUM (99.999%) Trimethylgallium, Ga(CH3)3 , often abbreviated to TMG or TMGa, commonly used metalorganic source of gallium for metalorganic vapour phase epitaxy (MOVPE) for preparation of gallium-containing compound semiconductors used in fabricaton of optoelectronic devices and solar panels. In our synthethetic method the intermediate adduct of TMG is prepared which has no such limitation & can be stored for long time without any stringent safety precautions. The emphasis of Government on semiconductor chips manufacturing in India, will boost the demand indigenously sourced raw materials. Specifications: • TMG is a clear, colorless, pyrophoric liquid ie. catch fire on exposure to air. TMG is known to react violently with water and other compounds that are capable of providing labile and active hydrogen (i.e. protons). • TMG needs to be handled with care and caution, e.g. stored in a cool, dry place at 0-25 °C, under inert atmosphere, and ensuring that storage temperatures would not exceed 40 °C to avoid deterioration. Application: • Trimethylgallium, Ga(CH3)3, TMG or TMGa is commonly used metalorganic source of gallium for metalorganic vapour phase epitaxy (MOVPE) for preparation of gallium-containing compound semiconductors, such as:- • gallium arsenide (GaAs) (used in space applications, blue LED material galium nitride (GaN), • gallium phosphide (GaP), gallium antimonide (GaSb) (used in fabrication of optoelectronic devices), • copper indium gallium sulfide and copper indium gallium selenide (CIGS) (used in manufacture of high efficiency solar panels). • TMG is used for preparation of thin films of gallium based semiconductor materials which are used in micro-electronic and high speed devices.
    [Show full text]