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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON AUTOMOTIVE INNOVATION GREEN ENERGY VEHICLE: AIGEV 2018 - Kuantan, Malaysia (25–26 July 2018)] - Chemical bath deposition of In2S3 thin films as promising material and buffer layer for solar cells
摘要： The copper(I) and indium thin films are obtained by chemical bath deposition (CBD). Their elemental composition and microstructure were particularly studied by means of the x-ray photoelectron spectroscopy (XPS). The change in the surface microstructure of thin films depending on the temperature and the composition of reaction bath were determined by means of scanning electron microscopy (SEM).
关键词： chemical bath deposition,solar cells,thin films,buffer layer,In2S3
更新于2025-11-21 11:20:48
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Growth of graphene on SiO2 with hexagonal boron nitride buffer layer
摘要： One-through process of graphene growth on insulator substrates with inserting a hexagonal boron nitride (h-BN) buffer layer is expected to yield significant improvements in performance of electron transport properties of graphene devices due to the alleviation of the interface interaction between graphene and insulators and the enhancement of the flatness of the substrate. In this study, we successfully fabricated a graphene/h-BN/SiO2 heterostructure by direct chemical vapor deposition (CVD) without mechanical transfer processes. It was found that h-BN promotes the growth of graphene on SiO2 whereas the graphene growth without the h-BN layer is extremely difficult. The electronic structures of graphene and h-BN were investigated by using micro-Raman spectroscopy and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The B and N K-edge NEXAFS revealed that substitutional oxygen impurities with the chemical form of BN3?xOx (x = 1, 2, 3) are present in both h-BN/SiO2 and graphene/h-BN/SiO2. The number of O substitutional impurities is two times larger in graphene/h-BN/SiO2 than in h-BN/SiO2, which is presumed to be due to the reaction with oxygen from SiO2 and methanol during the graphene growth. The interfacial interaction between graphene and h-BN was found to be weak in graphene/h-BN/SiO2. The present study shows that the h-BN layer grown with CVD can be a superior buffer layer for graphene devices which enables direct graphene growth on it and to decrease the interactions with insulator substrates.
关键词： NEXAFS,h-BN,Chemical vapor deposition,Buffer layer,Graphene
更新于2025-09-23 15:23:52
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Doping induced performance enhancement in inverted small molecule organic photodiodes operating below 1V reverse bias - Towards compatibility with CMOS for imaging applications
摘要： Organic photodiodes (OPDs) offer a myriad of advantages over conventional inorganic photodetectors, making them particularly attractive for imaging application. One of the key challenges preventing their utilization is the need for their integration into the standard CMOS processing. Herein, we report a CMOS-compatible top-illuminated inverted small molecule bi-layer OPD with extremely low dark leakage current. The device utilizes a titanium nitride (TiN) bottom electrode modified by a [6,6]-phenyl C61 butyric acid methyl ester (PCBM) cathode buffer layer (CBL). We systemetically show that doping the CBL enhances device's low voltage (below 1 V reverse bias) photoresponse by increasing the linear dynamic range (LDR) and making the bandwidth of the photodidoe broader without compromising the leakage current. The optimized device exhibits a dark leakage current of only ~ 6 x 10-10 A/cm2 at -0.5 V. The external quantum efficiency (EQE) at 500 nm reaches 23% with a calculated specific detectivity as high as 7.15 x 1012 cm Hz1/2/W (Jones). Also the LDR approaches 140dB and the bandwidth is about 400kHz, at -0.5 V bias. The proposed device structure is fully compatible with CMOS processing and can be integrated onto a CMOS readout circuit offering the potential to be applied in high-performance large-scale imaging arrays.
关键词： Interface engineering,Doping,CMOS,Titanium nitride,Organic photodiode,Cathode buffer layer
更新于2025-09-23 15:23:52
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The contribution of AsH3: Pre-flow and V/III ratio effects on heteroepitaxially grown GaAs/Ge
摘要： We report the effects of AsH3 (arsine) on morphological, structural, optical and crystalline quality of MOVPE (metal organic vapor phase epitaxy) grown GaAs/Ge heterostructures. AsH3 pre-flow supplied on Ge substrate to have As atoms as a first atomic layer on the surface of Ge substrate. Additionally, the V/III ratio effects of LT-GaAs buffer layer, grown on arsenized Ge substrate, have been analyzed to have reduced APBs (anti-phase boundaries) in the interface between epilayer and Ge substrate. It has been considered that the optimal AsH3 pre-flow duration and V/III ratio of GaAs buffer layer extremely influence the effects of APBs even we have used miss-cut Ge substrate and grown by two-step growth technique to obtain double atomic step. It is shown that without AsH3 pre-flow the surface of GaAs epilayer becomes rougher while it is optically smooth under the longer AsH3 pre-flow. On the other hand, even the surface situation does not change with longer AsH3 pre-flow the structural, optical and crystalline qualities become worse because of the possible presence vacancies of created during the growth. Similar behavior has been observed for the V/III effects of GaAs buffer layer and it has resulted in low full width at half maximum of high-resolution X-ray diffraction and high photoluminescence peak intensity for the optimal V/III ratio.
关键词： Ge,Buffer layer,Arsine,MOVPE,GaAs
更新于2025-09-23 15:23:52
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Effect of RF power on the structural and optical properties of ZnS thin films prepared by RF-sputtering
摘要： Zinc sulphide (ZnS) thin films have grown on glass and Si substrates by reactive cathodic radio frequency (RF) sputtering. The RF power was varied in the range of 100 to 250 W, while the deposition time is set at 75 min. The optical, structural, and morphological properties of these thin films have been studied. The optical properties (mainly thickness, refractive index, absorption coefficient, and optical band gap) were investigated by optical transmittance measurements in the wavelength range of ultraviolet-visible-near infrared spectroscopy and spectroscopy infrared with Fourier transform. Fourier (FT-IR) and XRD analysis indicated that all sputtering ZnS films had a single-phase with a preferred orientation along the (111) plane of the zinc sphalerite phase (ZB). The crystallite size ranged from 11.5 to 48.5 nm with RF power getting a maximum of 200 W. UV–visible measurements exhibited that the ZnS film had more than 80% transmission in the visible wavelength region. In addition, it has been observed that the band gap energy of ZnS films is decreased slightly from 3.52 to 3.29 eV, and as the RF power is increased, the film thickness increases with the speed of deposit growth. Scanning electron microscopy observations revealed the types of smooth-surfaced films. The measurements (FT-IR) revealed at wave number 1118 and 465.02 cm?1 absorption bands corresponding to the symmetrical and asymmetric vibration of the Zn–S stretching mode. X-ray reflectometry measurements of ZnS films have shown that the density of the films is (3.9 g/cm3) close to that of solid ZnS.
关键词： RF-sputtering ZnS,ZnS buffer layer for solar cell,ZnS thin films by sputtered
更新于2025-09-23 15:23:52
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Homogeneous Large-area Quasi-freestanding Monolayer and Bilayer Graphene on SiC
摘要： In this study, we first show that the argon flow during epitaxial graphene growth is an important parameter to control the quality of the buffer and the graphene layer. Atomic force microscopy (AFM) and low-energy electron diffraction (LEED) measurements reveal that the decomposition of the SiC substrate strongly depends on the Ar mass flow rate while pressure and temperature are kept constant. Our data are interpreted by a model based on the competition of the SiC decomposition rate, controlled by the Ar flow, with a uniform graphene buffer layer formation under the equilibrium process at the SiC surface. The proper choice of a set of growth parameters allows the growth of defect-free, ultra-smooth and coherent graphene-free buffer layer and bilayer-free monolayer graphene sheets which can be transformed into large-area high-quality quasi-freestanding monolayer and bilayer graphene by hydrogen intercalation. AFM, scanning tunneling microscopy, Raman spectroscopy and electronic transport measurements underline the excellent homogeneity of the resulting quasi-freestanding layers. Electronic transport measurements in four-point probe configuration reveal a homogeneous low resistance anisotropy on both μm- and mm scales.
关键词： SiC terrace steps,polymer assisted sublimation growth,Epitaxial graphene,freestanding bilayer graphene,argon gas flow,graphene buffer layer,monolayer graphene,resistance anisotropy,large-scale graphene growth,freestanding monolayer graphene
更新于2025-09-23 15:22:29
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Polymer light-emitting displays with printed cathodes
摘要： High-resolution passive-matrix polymer light-emitting displays with printed cathodes are achieved by combining delicate cathode deposition and multifunctional buffer layer fabrication. Unlike other printing methods and printed materials, ink-jetting conducting nano-particles as cathode can provide high-resolution cathode patterns and excellent continuity along the fine cathode lines without any mechanical pressure on the organic layers. The buffer layer between the printed cathode and the organic active layers, was fabricated by mixing the water/alcohol-soluble polymer poly[9,9-bis(3’-(N,N-dimethylamino)propyl)-2,7-fluorene-alt-2,7-(9,9-dioctylfluorene)] (PFNR2) and a curable epoxy adhesive. It offers the functions of solvent-proof, electron-injection, and proper affinity with the cathode ink. While improving the performance of devices, especially blocking the leakage current greatly, the cross-linked buffer layer also induces a novel phenomenon of ‘linear η-J plot’, which can be derived to interesting and realistic results. Red, green, and blue monochrome and full-color polymer light-emitting displays with a content format of 96 × 3 × 64 show neither dead pixels nor dead lines. Under optimized steps of curing, the nano silver ink forms continuous, defect-free, and low-resistance cathode rows without any distortion. The red, green, and blue displays exhibit the current efficiencies of 0.62, 4.38 and 0.93 cd/A, and CIE color coordinates of (0.63, 0.37), (0.39, 0.57) and (0.18, 0.16), respectively. The cathode printing technique removes the need of high vacuum for thermal evaporation of the cathode metal, which could lead to the industrial roll-to-roll process to manufacture the flat panel displays.
关键词： Buffer Layer,PLED,Printed Cathode,Display
更新于2025-09-23 15:21:21
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Surfactant-free stable SnS2 nanoparticles dispersion for deposition of device-quality films
摘要： Tin sulfide (SnS2) has recently attracted considerable attention due to its layered structure that may form two dimensional morphologies. It is an n-type semiconductor with band gap and electron affinity similar to CdS and In2S3; therefore can be regarded as an alternative for these materials in thin film solar cells. Here, we synthesis of SnS2 nanoparticles with different morphology in different ratio of water-ethanol mixed solution by solvothermal method, and observe that more ethanol leads to large sheet like morphologies, while water based synthesis results in very small nanosheets. A challenge in wet deposition of device-quality thin films of SnS2 is the requirement for highly dispersed particles/sheets. We found highly polar dimethylformamide (DMF) as the right dispersing medium, yielding highly stable dispersions. Very uniform nanocrystalline thin films with [001] preferred orientation and good adhesion to substrate are simply deposited by drop casting and spin coating a 0.5 wt% DMF sol of SnS2 at 2000 rpm for 1 min. Electron affinity and band gap of the films are 4.33 eV and 2.27 eV, which is well aligned for copper indium gallium sulfo-selenide (CIGS) solar cells.
关键词： Two dimensional structures,Surfactant-free dispersion,copper indium gallium sulfo-selenide solar cells,SnS2 thin film,Dimethylformamide,Buffer layer
更新于2025-09-23 15:21:21
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Efficiency Enhancement of Cu(In,Ga)(S,Se)2 Solar Cells by Indium-doped CdS Buffer Layer
摘要： Improving power conversion efficiency of photovoltaic devices has been widely investigated, however, most of researches mainly focus on the modification of the absorber layer. Here, we present an approach to enhance the efficiency of Cu(In,Ga)(S,Se)2 (CIGSSe) thin-film solar cells simply by tuning the CdS buffer layer. The CdS buffer layer was deposited by chemical bath deposition. Indium doping was done during the growth process by adding InCl3 into the growing aqueous solution. We show that the solar cell efficiency is increased by properly Indium doping. Based on the characteristics of the single CdS (with or without In-doping) layer and of the CIGSSe/CdS interface, we conclude that the efficiency enhancement is attributed to the interface-defect passivation of heterojunction, which significantly improves both open circuit voltage and fill factor. The results were supported by SCAPS simulations, which suggest that our approach can also be applied to other buffer systems.
关键词： CdS buffer layer,interface passivation,SCAPS simulations,Indium doping,CIGSSe-based solar cell
更新于2025-09-23 15:21:01
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An inverted ZnO/P3HT:PbS bulk-heterojunction hybrid solar cell with a CdSe quantum dot interface buffer layer
摘要： An inverted bulk-heterojunction (BHJ) hybrid solar cell having the structure ITO/ZnO/P3HT:PbS/Au was prepared under ambient conditions and the device performance was further enhanced by inserting an interface buffer layer of CdSe quantum dots (QDs) between the ZnO and the P3HT:PbS BHJ active layer. The device performance was optimized by controlling the size of the CdSe QDs and the buffer layer thickness. The buffer layer, with an optimum thickness and QD size, has been found to promote charge leading to an increased open-circuit voltage (VOC), extraction and reduces interface recombinations, short circuit current density (JSC), fill factor (FF) and power conversion efficiency (PCE). About 40% increase in PCE from 1.7% to 2.4% was achieved by the introduction of the CdSe QD buffer layer, whose major contribution comes from a 20% increase of VOC.
关键词： CdSe quantum dots,inverted bulk-heterojunction,interface buffer layer,hybrid solar cell,power conversion efficiency
更新于2025-09-23 15:21:01