15 August 2018 Fe-modified perovskite-type NaMgF3 photocatalyst: Synthesis and photocatalytic properties Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): Kun Nie, Hanpei Yang, Zhao Gao, Junming Wu Fe-modified perovskite-type NaMgF3 photocatalysts were synthesized via a microemulsion method followed by calcinations. The as-prepared catalysts were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Brunauer–Emmett–Teller specific surface areas (BET) measurements, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), and Photoluminescence spectroscopy (PL). The photocatalytic activity of as-prepared materials was obtained via degradation of aqueous Rhodamine B. Results demonstrate that the Mg2+ in NaMgF3 may be substituted by a low amount of Fe3+, forming a finite solid solution NaMg1-xFexF3(x
15 August 2018 Mg thermal diffusion behavior on the band modulation of MgxZn1-xO/ZnO metal-semiconductor-metal photodetectors Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): J.D. Hwang, J.S. Lin, S.B. Hwang By magnesium (Mg) atom diffusion in ZnO layer, the detection band of MgxZn1-xO/ZnO metal-semiconductor-metal photodetectors (MSM-PDs) could be modulated from two distinct bands to one band. ZnO and MgxZn1-xO layers were deposited consecutively on a sapphire substrate using an radio-frequency magnetron sputtering system. With increasing annealed temperature, Mg atoms diffuse from MgxZn1-xO into the underlying ZnO layer, which tunes the composition of ZnO into MgyZn1-yO and thus modulate the detection band of MSM-PDs. For the annealed temperature below 900
15 August 2018 Rear-surface line-contact optimization using screen-print techniques on crystalline solar cells for industrial applications Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): Jiajer Ho, Te-Chun Wu, Jyh-Jier Ho, Chih-Hsiang Hung, Sung-Yu Chen, Jia-Show Ho, Song-Yeu Tsai, Chau-Chang Chou, Chi-Hsiao Yeh This paper explores the utility of single-crystalline silicon solar cells that are treated with the screen-print technique to implement line contacts at the cells’ rear surfaces. We designed rear-surface line-contact (RSLC) solar cells using screen-print methods on n-type wafers (125
15 August 2018 Impact of isotropic strain on electronic and magnetic properties of O-adsorbed SiC monolayer Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): Min Luo, Yu-E. Xu, Yu-Xi Song Electronic and magnetic properties of two-dimensional (2D) silicon carbide (SiC) with the O adatom have been studied by the first-principles calculations. Different adsorption sites have been investigated. Magnetism is observed, while the O adatom binds to Si or situates in the middle of hexagons. We further study the effects of strain on the magnetism in the O-adsorbed 2D-SiC, we apply an isotropic tensile and compressive strain on the system. On the basis of our calculations, tunable magnetism shows as the strain increases. The analysis of the PDOS shows that the p-p hybridization between O and C/Si atoms results in such magnetic behavior. Moreover, under the compressive strain, the O-adsorbed SiC monolayer could transfer from semimetal to metal states. The adsorption of the O atom might show potential applications in SiC-based nanoscale devices.
15 August 2018 Effects of interfacial layer-by-layer nanolayers on the stability of the Cu TSV: Diffusion barrier, adhesion, conformal coating, and mechanical property Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): Daekyun Jeong, Rahim Abdur, Young-Chang Joo, Jae-il Jang, Pil Ryung Cha, Jiyoung Kim, Kyeong-Sik Min, Jaegab Lee The Through-Silicon (Si) Via (TSV) is the integration technology for three-dimensional integrated-circuit packaging. The layer-by-layer (LbL) technique has been used to deposit flexible poly(allylamine) hydrochloride (PAH)/polystyrene sulfonate (PSS) multilayers inside scalloped Si trenches of a high aspect ratio, fabricated by the Bosch-etching process. An outstanding control of the thickness and the conformality of the polymer layers, along with a significantly improved planarization, was achieved due to the LbL-technique self-termination effects. In addition, the basic properties of the polymer layers have been characterized: diffusion-barrier properties, adhesion, density, and elastic modulus. The results of this study demonstrate the feasibility of LbL multilayers regarding the TSV liner for the vertical interconnect accesses with a high aspect ratio of highly scalloped surface walls.
15 August 2018 Structure, optical, electrical and thermoelectric properties of solution-processed Li-doped NiO films grown by SILAR Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): N.P. Klochko, K.S. Klepikova, D.O. Zhadan, S.I. Petrushenko, V.R. Kopach, G.S. Khrypunov, V.M. Lyubov, S.V. Dukarov, V.O. Nikitin, M.O. Maslak, A.Yu. Zakovorotniy, A.L. Khrypunova The article presents a new facial synthesis of Li-doped NiO films (NiO:Li) via an easy and cost-effective method Successive Ionic Layer Adsorption and Reaction (SILAR) with the processing of the obtained NiO films in a lithium-containing aqueous solution for their transformation after annealing into NiO:Li layers. Comparative analysis of crystal structure, optical, electrical and thermoelectric properties of the obtained NiO and NiO:Li 420-1050
1 August 2018 Study on characterization method of optical constants of germanium thin films from absorption to transparent region Publication date: 15 August 2018 Source:Materials Science in Semiconductor Processing, Volume 83 Author(s): Huasong Liu, Shida Li, Peng Sun, Xiao Yang, Dandan Liu, Yiqin Ji, Feng Zhang, Deying Chen, Yuping Cui In this paper, the physical dispersion model of the optical constants of the amorphous germanium thin films was studied. Based on the Cody-Lorentz model, the optical constants of the films are characterized from the visible region to the long-wave infrared region. The optical constants are calculated from the inverse calculation of the reflection spectrum and the transmission spectrum in visible region. The calculated optical constants are extended to the infrared transparent region of the germanium thin films, which is consistent with the actual measurement results. The calculated optical constants are verified by the Cauchy model in the transparent region. According to the properties of band gap and tail width, the physical mechanism why the refractive index and extinction coefficient of films is greater than that of bulk material was determined. The decay rate of the germanium film in the long wave direction is lower than that of the germanium crystal due to the presence of the tail state in the germanium film material. Therefore, the refractive index and extinction coefficient of the film are greater than those of the bulk material.
1 August 2018 Editorial Board Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82
1 August 2018 Red light emitting diodes based on the type-II InGaN-ZnSnN2/GaN quantum wells Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Anup Gorai Several approaches have been tried by researchers for improvement of the InxGa1-xN/GaN QW red LEDs, where due the strong polarization fields, the electron-hole wave functions are separated spatially. In this paper, we have studied the type–II InGaN-ZnSnN2/GaN QW diodes and compared the results with the conventional InGaN/GaN QW diodes for red emission. It reveals that the overlap of electron- hole wave functions are increased more than three times that of the conventional InGaN/GaN QWs. In the active region with lower In-content, hole confinement increases due to higher valance band offset in the type-II structure and the electron-hole wave functions move towards the center of the well. The entire red region of the visible spectrum can be covered with suitable width, position of the ZnSnN2 layer and In content in the InGaN layer. The computations have been carried out through the self-consistent solutions of the Schr
1 August 2018 Facile synthesis of copper oxide microflowers for nonenzymatic glucose sensor applications Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Victor Vinoth, Thomas Daliya Shergilin, Abdullah M. Asiri, Jerry J. Wu, Sambandam Anandan In this manuscript, an attempt has been made to synthesize well-crystallized flower-shaped copper oxide hierarchical structures by simple solution process for fabrication of nonenzymatic glucose sensor under alkaline conditions. Scanning and Transmission electron micrographs clearly illustrate that CuO structures are flower-like shape while X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) analyses indicate the formation of pure CuO monoclinic phase. Modified electrode with CuO microflowers shows a wide linear response towards glucose in the concentration range of 10–120
1 August 2018 Green synthesis of zinc oxide nanoparticles using Atalantia monophylla leaf extracts: Characterization and antimicrobial analysis Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): S. Vijayakumar, S. Mahadevan, P. Arulmozhi, S. Sriram, P.K. Praseetha In the recent decades, nanotechnology has become an important research field of modern material science. Green synthesized nanoparticles have garnered wide interest due to its inherent features like rapidity, eco-friendly and cost-effectiveness. For the first time, Zinc Oxide nanoparticles were successfully synthesized using Atalantia monophylla leaf extract in the present's investigation. The biosynthesized Zinc Oxide nanoparticles were characterized by UV- Vis spectrophotometer, Fluorescence spectrometer (PL) and their peaks were identified to be at 352 and 410
1 August 2018 Co0.5Zn0.5Fe2O4/Ag3PO4: A magnetic, highly efficient visible-light photocatalyst and the Z-scheme mechanism for removal of anionic dye and tetracycline hydrochloride Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Cuiping Lin, Xin Xie, Chen Li, Qishe Yan The magnetic Co0.5Zn0.5Fe2O4 incorporated Ag3PO4 photocatalysts were fabricated by facile sol-gel and hydrothermal route. The resulting Co0.5Zn0.5Fe2O4/Ag3PO4 composites were characterized by XRD,1X-ray diffraction. SEM,2Scanning electron microscope. UV–vis DRS,3UV–vis diffuse reflectance spectrum. FT-IR4Fourier transfer infrared spectroscopy. and VSM.5Vibrating sample magnetometer. The results indicated that the magnetically separable composites with good dispersity showed a strong absorption in the uv–vis region and the saturation magnetization was 85.25
1 August 2018 Characterization of recrystallized depth and dopant distribution in laser recovery of grinding damage in single-crystal silicon Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Keiichiro Niitsu, Yu Tayama, Taketoshi Kato, Hidenobu Maehara, Jiwang Yan A nanosecond pulsed Nd:YAG laser was irradiated on a boron-doped single-crystal silicon wafer with a diamond grinding finish to recover the grinding-induced subsurface damage. In order to visualize and measure the depth of the laser melted/recrystallized layer, small-angle beveled polishing was performed in pure water followed by KOH etching. It enabled the direct observation of the recrystallized region using a differential interference microscope and the measurement of its depth using a white light interferometer. Crystallinity analysis of the recrystallized region was carried out by using laser micro-Raman spectroscopy, and the dopant concentration profile was characterized by using radio frequency glow discharge optical emission spectrometry (rf-GD-OES). The results showed that the crystallinity and boron distribution in the recrystallized region changed after laser recovery. The dopant concentration becomes higher at the boundary of the recrystallized region and the bulk. This study demonstrates the possibility of boron concentration control by using suitable laser parameters.
1 August 2018 An X-ray photoelectron spectroscopy depth profile study on the InGeNi/(110) cleaved GaAs structure Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Constantin Catalin Negrila, Mihail Florin Lazarescu, Constantin Logofatu, Rodica V. Ghita, Costel Cotirlan InGeNi ohmic contacts on n-type semi-insulating GaAs(110) cleaved surfaces were fabricated. Cleaving semiconductor single crystal ensures the obtaining of semiconductor surfaces almost ideal in terms of chemical purity and stoichiometry. The chemical depth profile of metallic layer was investigated and revealed through multiple alternating steps of Ar+ etchings and XPS (x-ray photoelectron spectroscopy) measurements. The metallic layers made of alloy of Ge, In and Ni (60
1 August 2018 Effect of surface states on monolayer doping: Crystal orientations, crystallinities, and surface defects Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Chul Jin Park, Sang Min Jung, Jin Hwan Kim, Il To Kim, Moo Whan Shin Monolayer doping (MLD) has been regarded as the most suitable doping method for future semiconductor devices. MLD based on surface functionalization can be seriously affected by the surface states, including the orientations, crystallinities, and defects. We report for the first time the effect of surface states on boron-MLD (B-MLD) process and discuss the applicability of MLD for a fin structures. Depending on the surface states, the monolayer formation reaction is restricted, which causes more than five-fold differences in the doping level. Therefore, the surface states should be gravely considered before applying MLD and are crucial constraints in the MLD process on non-planar structures that have different surface states depending on its structural position. The B-MLD process on as-cleaned (100) and (110) silicon surfaces provides doping levels of 4.69
1 August 2018 MoS2 compounded bidirectionally with TiO2 for hydrogen evolution reaction with enhanced humidity sensing performance Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Xiaofan Chen, Haoqi Hu, Yu Feng, Deyan Peng, Bo Li, Hao Fu, Bangjun Guo, Xiang Lei, Ke Yu A proper catalyst is the key factory for hydrogen evolution reaction (HER). Both MoS2 and TiO2 are regarded as potential candidates for HER, because MoS2 possesses a large number of active edge site and TiO2 has hydrophobic with special structure. In this work, MoS2 and TiO2 are compounded bidirectionally for unique morphology by two-step hydrothermal method. The hydrogen evolution properties of two kinds of subsequent composites are studied for the first time. The active sites for HER of the two composite catalysts are increased greatly after compounding, so is their specific surface area. As a result, the Tafel slope of TiO2@MoS2 and MoS2@TiO2 are reduced to 70.6
1 August 2018 Exploring the photoluminescence emission behaviour of vacuum deposited Sb2O3 thin film having randomly oriented thorn like structures Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): K.V. Divya, Paulose Thomas, K.E. Abraham An intense UV–visible photoluminescence of vacuum deposited Sb2O3 thin film surface crowded with randomly oriented thorn like structures have been studied using photoluminescence (PL) spectroscopy. The resulting UV emissions are near band edge (NBE) emissions. All the visible deep level emissions (DLE) are due to oxygen defect states. The thorn like structures is achieved by the inclined arrangement of substrates with respect to the source in the vacuum chamber. Some distorted polygonal shapes also emerge among the randomly oriented thorns giving an impression of a hybrid formation upon annealing. This formation of various structures leads to decreased UV NBE and defect level PL emission. The excitation wavelength dependence of PL emission has also been studied. The optical band gap energy of the film is found to be varying from 3.64 to 3.42
1 August 2018 Metal-induced growth of crystal Si for low-cost Al:ZnO/Si heterojunction thin film photodetectors Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Chong Tong, Eric S. Kozarsky, Joondong Kim, Juhyung Yun, Wayne A. Anderson Quality crystal silicon (Si) thin films were grown via the metal-induced growth (MIG) method, which is a low-cost and metal-silicide assisted technique. The metal catalysts of Ni, Pd and Co were first deposited onto substrates for silicide template layer formation. Then, crystal Si thin films with a thickness of ~ 5
1 August 2018 In-situ loading of (BiO)2CO3 on g-C3N4 with promoted solar-driven photocatalytic performance originated from a direct Z-scheme mechanism Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Jiao Huang, Huanhuan Liu, Jiufu Chen, Junbo Zhong, Jianzhang Li, Ran Duan The photocatalytic performance of g-C3N4 has been significantly hindered by its inherent drawbacks; therefore it is highly desirable to ameliorate the photocatalytic performance of g-C3N4. Construction of effective direct Z-scheme photocatalysts is facile approach to boost the separation and transfer of charge pairs, remarkably promoting the photocatalytic performance of the catalysts. Herein, (BiO)2CO3/g-C3N4 heterojunctions with improved solar-driven photocatalytic performance were in-situ constructed by loading (BiO)2CO3 onto the surface of g-C3N4 via a hydrothermal route. The (BiO)2CO3/g-C3N4 heterojunctions were optimized by adjusting the molar ratio between two components. The resulting heterojunctions display much higher photocatalytic activities for rhodamine B (RhB) degradation compared to the pristine g-C3N4 and the 1.5% sample exhibits the highest photocatalytic activity. Based on the surface photovoltage spectroscopy (SPS), the enhanced photocatalytic performance of (BiO)2CO3/g-C3N4 catalysts can be definitely assigned to the significantly promoted charge transfer and separation. The results confirm that the photoinduced charge separation of (BiO)2CO3/g-C3N4 composites obeys a direct Z-scheme mechanism, proven by the results of electron spin-resonance (ESR) and band edge potential.
1 August 2018 Equivalent circuit analysis of Al/rGO-TiO2 metal-semiconductor interface via impedance spectroscopy: Graphene induced improvement in carrier mobility and lifetime Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Mrinmay Das, Joydeep Datta, Sayantan Sil, Arka Dey, Rajkumar Jana, Soumi Halder, Partha Pratim Ray A metal-semiconductor (MS) contact often gives rise to a Schottky barrier junction and is immensely important in electronic devices. Recently, graphene and its nanocomposites have attracted interest for their tremendous potential in schottky barrier diodes (SBDs). To realize a high performance SBD, detail characterization of the MS interface is of utmost importance. In this regard, here we employ impedance spectroscopy (IS) as a simple yet powerful technique for the equivalent circuit analysis and characterization of Al/reduced graphene oxide(rGO)-TiO2 interface. Al/rGO-TiO2 SBDs are fabricated with different weight ratios of rGO (rGO:TiO2 =
1 August 2018 Material removal of single crystal 4H-SiC wafers in hybrid laser-waterjet micromachining process Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): Shaochuan Feng, Chuanzhen Huang, Jun Wang, Hongtao Zhu Yield stress, as well as ultimate stress, decreases with an increased temperature. A much smaller cutting force can be applied to perform the machining at high temperatures. Material is considered “softened” when its yield and ultimate stresses decrease due to the increase of temperature. During the hybrid laser-waterjet micromachining process, the material is heated by laser. Once the critical resolved shear stress (CRSS), related to the yield stress, decreases to be equal to the applied resolved shear stress induced by the pressurized waterjet impingement, the material begins to be deformed and then removed plastically. The hybrid laser-waterjet micromachining technology shows a satisfying performance on almost damage-free and high-efficient micromachining of thermal-sensitive and hard-brittle materials at their “softened” status. The present study is focused on the material removal mechanism of single crystal 4H-SiC in the hybrid laser-waterjet micromachining process. The temperature-dependent CRSS on the primary slip system of 4H-SiC is formulated. It is shown that the CRSS of 4H-SiC is less than 5
July 2018 A simple, one-pot, low temperature and pressure route for the synthesis of RGO/ZnO nanocomposite and investigating its photocatalytic activity Publication date: 1 August 2018 Source:Materials Science in Semiconductor Processing, Volume 82 Author(s): S.M. Baizaee, M. Arabi, A.R. Bahador A simple, low temperature and pressure, catalyst-free reflux method was reported for the synthesis of reduced graphene oxide (RGO)/ZnO nanocomposite (NC). Formation of ZnO Nanoparticles (NPs) on the surface of Graphene oxide (GO) sheets was led to reduction of GO and fabricating RGO/ZnO NC. The photoluminescence (PL) analysis showed two broad and intense peaks in PL spectra of ZnO and RGO/ZnO samples which are assigned to the electronic transition from zinc interstitial levels (IZn) to Zinc vacancy levels (VZn) and from conduction band to the oxygen vacancy levels (VO), respectively. Broad and intense peaks in PL spectra of ZnO NPs synthesized by our method makes many photogenerated e-h pairs in trap levels due to large number of trap levels. Hybridizing ZnO NPs with GO considerably improve photocatalytic activity of samples due to transferring these electrons to GO sheets and preventing e-h recombination. XRD and FT-IR analyses confirmed that the as-obtained NC is in the form of RGO/ZnO instead of GO/ZnO. Synthesizing NCs by this route largely enhanced photocatalytic activity of NCs, because this synthesis route generates many trap state energy levels such as VO, VZn and IZn subband energy levels in the band gap of ZnO NPs. These numerous trap states -compared to that of RGO/ZnO NCs obtained by other methods- play an important role in the photocatalytic performance of synthesized NCs by enhancing the visible light absorption due to the resulting ZnO band gap narrowing.
July 2018 Editorial Board Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81
July 2018 Sonochemical synthesis of CuIn0.7Ga0.3Se2 nanoparticles for thin film photo absorber application Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Amol C. Badgujar, Rajiv O. Dusane, Sanjay R. Dhage CuInGaSe2 (CIGS) has been considered as promising solar absorber material for thin film solar cells leading to efficiencies exceeding 22% on lab scale. CIGS thin film solar cells fabricated from CIGS nanoparticles (NPs) inks by nonvacuum techniques is essential for cost effective cell fabrication process and for upscaling. In this regard, one step sonochemical synthesis of CIGS NPs employing relatively non-toxic precursors of metallic salts and selenourea in an aqueous medium under ambient conditions is being presented. Precursor ratios and sonication time were optimized to realize high-quality chalcopyrite crystal phases of CIGS NPs obtained by sonochemical route. X ray diffraction, UV–vis–NIR, Raman, Energy dispersive spectroscopy and Transmission electron microscopy confirmed the formation of tetragonal chalcopyrite CIGS NPs with a band gap of 1.42
July 2018 Addressing the issue of under-utilization of precursor material in SILAR process: Simultaneous preparation of CdS in two different forms – Thin film and powder Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): K. Ravichandran, S. Porkodi To overcome the major limitation of the successive ionic layer adsorption and reaction (SILAR) technique – the under-utilization of the precursor material – in the present work, simultaneous fabrication of CdS thin films and CdS powder is attempted.CdS films were prepared by employing SILAR technique using cadmium acetate dihydrate and thiourea as cationic and anionic precursor materials for Cd and S, respectively. The precipitated powder materials in the cationic and anionic baths which are usually discarded as wastage are collected and processed to obtain CdS powders. In another trial, the cationic and anionic bath solutions are mixed and the resultant precipitate is collected for characterization. The obtained CdS in thin film and powder forms are analyzed for structural, surface morphological, optical, compositional and photocatalytic properties. The results clearly showed that the obtained CdS films are good candidates for considering them for solar cell applications. Similarly, CdS powders obtained from the mixture of cationic and anionic bath solutions are found to have good photocatalytic efficacy. Thus the demerits of under-utilization of precursor materials in SILAR process for the deposition of CdS films is overcome to certain extent as 63% of the wastage is recovered as useful product.
July 2018 Muscovite mica as a flexible substrate for transparent conductive AZO thin films deposited by spray pyrolysis Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): M. Nasiri, S.M. Rozati In this study, Aluminum doped and undoped ZnO transparent conductive oxide thin films on a specific substrate, i.e., the muscovite mica sheet, were prepared by the spray pyrolysis technique. The substrate was used in this study for its unique properties, namely simultaneous flexibility and high thermal stability. The effects of doping on structural, morphological, optical and electrical characteristics of the samples were investigated and discussed. The obtained thin films were mostly polycrystalline with a hexagonal structure. UV–Visible spectroscopy analysis showed high average transparency (more than 80%) in visible and near-infrared region. Field emission scanning electron microscopy analysis proved the homogenous morphology of the films and showed their resistivity to be in the range of 10
July 2018 Characterization of bilayer AZO film grown by low-damage sputtering for Cu(In,Ga)Se2 solar cell with a CBD-ZnS buffer layer Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Woo-Jung Lee, Dae-Hyung Cho, Jae-Hyung Wi, Won Seok Han, Boo-Kyoung Kim, Sang Dae Choi, Ju-Yeoul Baek, Yong-Duck Chung Chemical bath deposition (CBD)-ZnS is used as a buffer layer for Cu(In,Ga)Se2 (CIGS) solar cell and then, plasma damage originated from the negative oxygen ions or neutral particles with high energy is regarded as an important issue during subsequent deposition of window layer by sputtering process. To avoid negative plasma effects, we newly designed sputtering system with dual deposition mode of low damage sputtering (LDS) process and direct sputtering (DS) process, adjusting plasma direction by dual cylindrical targets. It allows to grow bilayer AZO film by sequentially depositing thin LDS AZO film as a protect layer and thick AZO film as a transparent conducting layer to collect electrons. The physical and electrical characteristics of bilayer AZO film were investigated to verify the positive effect against plasma damage. In plasma damage test using GaAs wafer, we observed that increase of sputtering power leads to a falling-off in electrical qualities by plasma damage. For practical solar cell application, we fabricated three types of CIGS/CBD-ZnS solar cells with LDS AZO film grown at 2
July 2018 Enhanced infrared sensing properties of vanadium pentoxide nanofibers for bolometer application Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Sudharshan Vadnala, Nirupam Paul, Amit Agrawal, S.G. Singh The main aim of this work is to report an alternative technique of creating vanadium pentoxide (V2O5) based uncooled infrared (IR) detector, by a state-of-the-art V2O5 nanofibers, manufactured by facile and economical electrospinning process. The nanofibers were thermally and electrically characterized to determine their bolometric performance. The nanofibers show maximum voltage responsivity () 6987.3
July 2018 Low resistance Ga-doped ZnO ohmic contact to p-GaN by reducing the sputtering power Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Wen Gu, Xingyang Wu, Jianhua Zhang Ga-doped ZnO (GZO) thin films were deposited on p-GaN as transparent conducting layers (TCLs) of GaN-based LEDs by radio-frequency (RF) magnetron sputtering. The sputtering power effects on the electrical properties of GZO contacts to p-GaN were studied. It was found that low resistance ohmic contact with a specific contact resistance of 6.0
July 2018 Study on the deliquescence of AlSb/Sb stacks deposited by pulsed laser deposition Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Xiaolan Liu, Jiyang Liu, Ke Yang, Siying He, Hongting Lu, Bing Li, Guanggen Zeng, Jingquan Zhang, Wei Li, Lili Wu, Lianghuan Feng AlSb is a new type of optoelectronic material with wide potential application prospects, but the applications of AlSb thin films for solar cells were few reported before, owing to the intrinsic drawbacks of deliquescence for AlSb. In this work, four types of AlSb/Sb stacks were fabricated by using pulsed laser deposition: (1) AlSb/Sb (5
July 2018 Facile synthesis of CdZnS QDs: Effects of different capping agents on the photoluminescence properties Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Muhammad Masab, Haji Muhammad, Faheem Shah, Muhammad Yasir, Muddasir Hanif The luminescent semiconductor QDs are important materials because of applications in lasers, sensors, light-emitting diodes, biomedical labeling, biomedical imaging and solar cells. We have systematically studied the influence of five different capping agents on the structural and optical characteristics of CdZnS quantum dots (QDs) synthesized by the simplest aqueous method. The modified QDs were characterized by the UV–visible spectroscopy, X-ray diffraction, steady-state photoluminescence (PL), time-resolved PL, and transmission electron microscopy. We found that band-gap and PL characteristics of CdZnS QDs can be varied by using different capping agents. The CdZnS QDs capped with ethylene diamine (EDA) and mercaptoacetic acid (MAA) showed high PL intensities when compared to other capping agents. The UV–Vis absorption spectra were used to calculate the optical band-gaps: 2.63
July 2018 Electrical characterization of defects introduced during sputter deposition of tungsten on n type 4H-SiC Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Shandirai M. Tunhuma, F.D. Auret, M.J. Legodi, J. Nel, M. Diale We have studied the defects introduced in n-type 4H-SiC during sputter deposition of tungsten using deep-level transient spectroscopy (DLTS). Current-voltage and capacitance-voltage measurements showed a deterioration of diode thermionic emission characteristics due to the sputter deposition. Two electrically active defects E0.29 and E0.69 were introduced. Depth profiling revealed that sputter deposition increases the concentration of the native Z1 defect. A comparison with prominent irradiation and process induced defects showed that the E0.29 was unique and introduced during sputter deposition only. The E0.69 may be silicon vacancy related defect.
July 2018 Heterogeneous SnO2/ZnO nanoparticulate film: Facile synthesis and humidity sensing capability Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): A.S. Ismail, M.H. Mamat, M.F. Malek, M.M. Yusoff, R. Mohamed, N.D. Md. Sin, A.B. Suriani, M. Rusop Highly sensitive and extremely thin tin oxide/zinc oxide (SnO2/ZnO) heterojunction films were prepared via a two-step solution-based method for humidity-sensing application. The average diameters of the ZnO and SnO2 nanoparticles were 26 and 6
Effects of electromagnetic directional solidification conditions on the separation of primary silicon from Al-Si alloy with high Si content Publication date: July 2018 Source:Materials Science in Semiconductor Processing, Volume 81 Author(s): Guoqiang Lv, Yu Bao, Yufeng Zhang, Yunfei He, Wenhui Ma, Yun Lei In the present work, a continuous growth model of primary silicon from Al-Si melts was established based on the experimental and numerical data to analyze the separation mechanism of primary silicon from Al-Si alloy with high silicon content during electromagnetic directional solidification process. Results show that the separation of primary Si from Al-Si melts depends on the growth rate of primary Si phase and the solidification rate of the melts. Moreover, the separation and enrichment effects of primary Si during the electromagnetic directional solidification process could be improved by enhancing the bottom cooling conditions of crucible and the stirring strength of Al-Si alloy melts. Finally, the distribution and composition of phases and microstructures of the Al-Si alloy after the electromagnetic directional solidification technique were also analyzed and discussed. view: 225