Materials Express 2158-5849/2019/9/265/008 Copyright © 2019 by American Scientific Publishers All rights reserved. doi:10.1166/mex.2019.1494 Printed in the United States of America www.aspbs.com/mex Influence of boron nitride nanoparticles in the electrical and photoconduction characteristics of planar boron nitride-graphene oxide composite layer Harith Ahmad1, 2, ∗ and Tamil Many K. Thandavan1 1Photonics Research Centre, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia 2Visiting Professor at the Department of Physics, Faculty of Science and Technology, Airlangga University, Surabaya 60115, Indonesia Article ABSTRACT IP: 192.168.39.211 On: Mon, 27 Sep 2021 01:54:43 Copyright: American Scientific Publishers A modified Hummer’s method is used to obtainDelivered a photoconducting by Ingenta material based on boron nitride (BN)– graphene oxide (GO) composite layer. The proposed silver/BN–GO/silver Schottky photodetector was fabricated using a drop-casting technique and electron beam evaporation. It was characterized using field emission scan- ning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The confine element composition of boron, nitrogen, carbon, and oxygen showed excel- lent photoconduction toward laser wavelength of 650 nm and output power of 0.7 mW. The dark and illuminated current–voltage characteristics were used to determine the ideality factor and barrier height, which inevitably simplified the transport mechanism in the device. The reported ideality factor of 2.58 suggests the charge transport at the junction and formation of non-amorphous BN–GO composite layer. Keywords: Photodetector, Boron Nitride, Graphene Oxide, Ideality Factor, Barrier Height, Visible. 1. INTRODUCTION Their properties such as high mechanical and thermal The rapid growth of new functional two-dimensional (2D) stability and large piezoelectric constant incorporated in materials has attracted considerable interest in photocon- quantum wells, modulation-doped heterointerfaces, and duction technology due to their usefulness primarily in heterojunction structures provide access to wider spectral defense, sensors, health, and weather forecast systems.1 regions for optoelectronic devices.3 However, these mate- In addition, III-nitride-based materials such as gallium rials have lattice mismatch and thermal incompatibility nitride (GaN), aluminium nitride (AlN), and indium nitride with most substrates. Given these limitations, researchers (InN) have been widely used as ternary and quaternary have shifted their attention to boron (B)-based nitride III-nitride structures due to their bandgaps of 6.2, 3.4, and materials. Boron nitride (BN) has exceptional hexagonal 0.7 eV, respectively. These materials enable the bandgap and cubic forms (hBN and cBN)1 4 similar to the struc- to be tuned, allowing for wide-spectrum absorption from ture and properties of graphite and diamond,5 respec- 2 the deep ultraviolet (UV) region to whole visible range. tively. It can be synthesized in nanostructures with various morphologies for solar-blind deep UV photodetection.6 7 ∗Author to whom correspondence should be addressed. The bandgap of BN is similar to that of diamond Email: [email protected] and can be modulated even lower than 2.0 eV through Mater. Express, Vol. 9, No. 3, 2019 265 Materials Express Influence of boron nitride nanoparticles in the electrical and photoconduction Ahmad and Thandavan modified synthesis techniques.8 Deposition of electrodes 2. EXPERIMENTAL DETAILS using electron beam deposition with cBN in between 2.1. Materials and Method the electrodes shows peak responsivity at 180 nm owing The prepared BN–GO composite material was used as the to the high homogeneity of electric field between the main source for the conversion of light signal into electri- electrodes.9 Plasma-enhanced chemical vapor deposition cal signal. The GO was prepared using a modified Hum- enables sulfur doping in cBN lattices, decreasing the mer’s method.26 27 The preparation of GO involved two bandgap to 4.78 eV.10 hBN with similar physical, struc- steps: (i) pre-oxidation of graphite flakes and (ii) further tural, and isoelectrical analogy of graphene enables syn- oxidation of the pre-oxidized graphite. Oxidizing solvents thetization with NSs such as nanosheets, nanotubes, and (100 mL of 98% sulfuric acid (H2SO4) and 15 mL of 11 12 nanorods compared with cBN NSs. 68% nitric acid (HNO3)) were mixed with 5.0 g of Mesh Surface modification or functionalization of large sur- 7-graphite flakes to form pre-oxidized graphite flakes. The face area of graphene13 with 2D materials is highly mixture was stirred thoroughly for 60 min at 200 rpm in promising due to the low cost of maintenance, high effi- an ice bath. In the second step, the pre-oxidized graphite ciency and speed, and good photosensitivity linearity in flakes were further oxidized using 15 g of potassium 14 15 wide light intensity range. Graphene and graphene permanganate (KMnO4) under constant stirring at 40 C oxide (GO) have direct bandgap between 0 eV and 1 eV for 30 min at 200 rpm. Then, 50 mL of 10% hydro- that can be chemically tuned to facilitate light-, humidity-, gen peroxide (H2O2) was mixed into the final solution to and sound-sensitive polarizers16 and allow the absorp- reduce excessive oxidation of pre-oxidized graphite flakes. tion of infrared (IR) photons for photodetection.17 GO is At this stage, the active oxidizing species of manganate well-known and ideal material as it possesses carboxyl and (Mn2O7−) were eliminated by H2O2. Finally, the mixture hydroxyl functional groups18 for multifunctional struc- was centrifuged at 15000 rpm for 30 min to obtain the GO ture with 2D materials.19 20 Functionalizing GO with BN supernatant. can maximize the structural and thermal properties of GO BN solution was prepared by dispersing 100 mg of BN powder in 50 mL of deionized water, which was then son- and maintain its optical properties. 21 Simulation studies icated for 5 h at room temperature. The solution was fur- on graphene–BN photodetector coupled with an optical ther centrifuged at 5000 rpm for 30 min to collect pure mode of a Si waveguide showIP: maximum 192.168.39.211 responsivity On: of Mon, 27 Sep 2021 01:54:43 BN supernatant. The collected BN supernatant was further 0.36 AW−1 and high speed operationCopyright: with a 3 American dB cut- Scientific Publishers Delivered bysonicated Ingenta for another 2 h before mixing with GO super- off at 42 GHz.22 The bandgap of GO can also be tuned natant obtained using the modified Hummer’s method at from 2.7 eV to 1.15 eV by using fructose.23 Recently, volume ratio of 0.2:1. The BN–GO liquid base material Article Huang et al. explored carbon-based 2D carbon nitride was further ultrasonicated for 6 h at 40 Cinordertobe nanosheets (CNNs) that show superior electron mobility drop-casted on SiO2/Si substrate for a fast drying process. and high specific surface area with more surface active This process would allow for strong adhesion between the sites. CNNs can be incorporated with 0D carbon nan- BN–GO composite layer and the Ag source and drain elec- odots, metal atoms, and semiconductor nanoparticles to trodes deposited using the electron beam evaporation sys- enhance the photocatalytic performance.24 Huang et al. tem. Initially, the Si was thermally oxidized to SiO2 with demonstrated that graphitic carbon nitride heterojunction 1500 nm thickness at temperatures of 800 C–1200 C. photoactive nanocomposites can be used for environ- This deposited SiO2 layer acts as a dielectric layer and mental protection and clean energy and show excellent avoids direct contact of the BN–GO composite layer and stability in the presence of organic pollutants under illumi- Ag electrodes with Si substrate.28 Thus, the photocon- nation and decomposition features of abundant hydroxyl duction is purely due to the BN–GO composite layer can radical. 25 be determined. Then, 1.0 L of BN–GO solution was In this work, a planar BN–GO-based photodetector dropped on the SiO2/Si substrate once the temperature was utilized using a low-cost drop-casting technique and reached 550 C. Initially, the temperature of the substrate modified Hummer’s method. Current–voltage (I–V )char- was set to decrease at a rate of 1 C/s from an initiated acteristics of the fabricated metal–semiconductor–metal- temperature of 650 C. structured Ag/BN–GO/Ag Schottky photodetector were evaluated to simplify the transport mechanism in the 2.2. Characterizations device. The efficiency of BN nanoparticles in the bulk The I–V characteristics of the photodetector under GO layer was effective as the photoconduction in the GO laser/light illumination were characterized using a Keithley bulk layer was not easily achieved. Thus, based on the 2410 SourceMeter unit as shown in Figure 1. Under the calculated ideality factor and barrier height of the BN– illumination of red laser source wavelength at 650 nm, the GO composite layer, the generation of electron–hole (e–h) photoresponsivity of the planar BN–GO composite pho- pairs under the illumination of red laser at 650 nm was todetector was determined using a Yokogawa DLM2054 evaluated. mixed signal oscilloscope. 266 Mater. Express, Vol. 9, 2019 Influence of boron nitride nanoparticles in the electrical and photoconduction Materials Express Ahmad and Thandavan distribution of BN nanoparticles in the BN–GO composite layer. 3.2. Raman and FTIR Analysis Figure 4(a) shows the Raman scattering spectrum of the BN–GO composite layer measured at room temperature. The Si peak at 521 cm−1 was attributed to the penetra- tion of Raman green laser 532 nm through the drop-casted Fig. 1. I–V measurement setup of planar BN–GO composite layer on BN–GO composite layer. A sharp and intense peak was SiO2/Si substrate.