科创中国

An R&D-scale hollow cathode sputtering (HCS) system has been designed and built at NJIT. It operates in reactive mode using metal targets and can deposit virtually any metal oxide. We survey the use of metal oxide layers in thin film PV and report the preparation by HCS of several oxides including ZnO, ZnO:Al (AZO), Zn_xSn_yO, Cd_xSn_yO, and Cu_2-xO. Oxynitrides have also been prepared. For AZO, an excellent electron mobility of 53.4 cm²/Vs has so far been achieved, close to a world record for an as-deposited, sputter-based AZO layer. Cu2-xO layers have been successfully utilized as a back contact in CdTe solar cells. Work is under way to prepare the entire front stack of CdTe solar cells, namely TCO/HRT/buffer, by hollow cathode sputtering.

Alan E. Delahoy;Sebastian Falk;Payai Patra;Roman Korotkov;Bastian Siepchen;寿 彭;Ken K. Chin

2016-11-18

Published in Micro & Nano Letters; Received on 26th August 2011; Revised on 29th September 2011 Highly dispersive and well crystallised aluminium-doped zinc oxide (AZO) nanoparticles (the mole ratio of Al to Zn was 0.02) were prepared by sol-gel combustion method. Two typical synthesised chemical reagents of urea and citric acid were employed to synthesise the AZO nanoparticles by investigating and comparing the physical properties and microstructural characteristics. The nanoparticles were characterised in detail by thermogravimetry and differential thermal analysis, bulk density measurement, transmission electron microscope and X-ray diffraction (XRD). The XRD patterns of AZO nanoparticles corresponded well to the hexagonal structure of pure ZnO, indicating that the Zn atom was substituted by Al atom. Small amount of urea in the precursor solution tends to generate larger amount of heat when the sol-gel is combusting. With increasing the content of urea in the precursor solution, the size of the prepared AZO nanoparticles varied from 17 to 25 nm. Simultaneously, obvious decrease in bulk density was observed when slightly increasing the ratio of the urea to the citric acid.

Chao Xu;Shimin Liu;Chaoqian Liu;Wanyu Ding;寿 彭;Weiping Chai

Micro and Nano Letters

2011

Transparent conducting Al-doped ZnO (ZnO:Al, AZO) thin films with good optical and electrical characteristics were prepared by direct current pulse magnetron sputtering. Textured surfaces of AZO films were obtained by etching with NaOH solution successfully and the effect of substrate temperature on the surface texture was investigated. The surface is covered with craters after etching with 5% NaOH solution, and the crater diameter decreases gradually as substrate temperature increases. For AZO film deposited at 270, the crater diameters is 0.5-1 μm, which is an effective surface texture for light trapping.

Ying Wang;有松 顾;寿 彭;Wanyu Ding;Hualin Wang;Weiping Chai

Applied Surface Science

2011-7-1

N doped TiO₂ films were deposited on glass substrates at room temperature using DC coupled RF magnetron sputtering with a TiO₂ ceramic target. The influences of N₂ flow rate on the deposition rate, crystal structure, chemical composition and band gap of the deposited films were investigated by Optical profiler, X-ray diffraction, X-ray photoelectron spectroscope and ultraviolet-visible spectrophotometer. The film growth rate gradually decreased with increasing N₂ flow rate. As N₂ flow rate increased, the crystallization of the films deteriorated, and the films tended to form amorphous structure. XPS analysis revealed that N dopant atoms were added at the substitutional sites into TiO₂ lattice structure. FE-SEM results showed that the grain size of the film decreased and the crystallinity degraded as N₂ flow rate increases. In addition, N doping caused an obvious red shift in the optical absorption edge.

寿 彭;Yong Yang;Gang Li;Jiwen Jiang;Kewu Jin;Ting Ting Yao;Kuanxiang Zhang;Xin Cao;Yun Wang;Genbao Xu

Journal of Alloys and Compounds

2016-9-5

AZO films were deposited on glass substrates by DC coupled RF magnetron sputtering at low temperature with a AZO ceramic target (2 wt% Al₂O₃), and then AZO films were etched by the 0.5 wt% HCl solution to obtain textured structures. Crystal phase structure, surface morphology, optical, electrical properties and the textured structure of AZO films mainly influenced by working pressure were characterized by XRD, SEM, spectrophotometer, hall effect test system and photoelectric haze instrument, respectively. The results show that AZO thin films with excellent performance can be prepared by DC coupled RF magnetron sputtering at low temperatures. With the decrease of working pressure, the compactness of AZO films increases, and their photoelectric performance improves, and textured structures with good light trapping effect is obtained by post etching. Under working pressure of 0.5 Pa, the resistivity of AZO thin films prepared at low temperature is 3.55×10^-4 Ω·cm, and the transmittance at visible light is 88.36%. After etching, their resistivity and transmittance at visible light are 4.19×10^-4 Ω·cm and 89.59%, respectively, and the haze reaches to 24.7%.

Kuanxiang Zhang;寿 彭;Tingting Yao;Xin Cao;Kewu Jin;Genbao Xu

Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering

2017-3-1

A series of novel Fe³⁺/TiO₂ nano-films were synthesized by sol-gel method. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible spectrophotometer. Influence of Fe doping content, storage time and film layers on the hydrophilicity of the film was investigated by contact goniometer. The photocatalytic activity of the film was evaluated by photocatalytic degradation of methylene blue under the UV light (8 W, λ=254 nm) irradiation. The results indicate that when the doping content of F³⁺ is 0.5% (mass fraction), the photocatalytic activity of the TiO₂ film is greatly promoted; furthermore, it also shows the best hydrophilicity, with the contact angle between water and the film approximating 0°.

寿 彭;Fangfang Cao;Liangmao Jin

Nami Jishu yu Jingmi Gongcheng/Nanotechnology and Precision Engineering

2014-11-15

In this work, a novel Ag/AgBr/ZnO SERS substrate was prepared by calcinating spin-coated zinc acetate on glass slides in the presence of ethanolamine (EA), followed by the process of impregnating-precipitation-photoreduction treatment. The SERS performances of Ag/AgBr/ZnO substrates were evaluated using aqueous crystal violet (CV) and Rhodamine 6G (R6G) as target analytes. The effects of initial immersion precursor concentration and irradiation time on the SERS performance were systematically studied. The as-prepared SERS substrate exhibited good chemical detection sensitivity, reproducibility and reusability. The optimal Ag/AgBr/ZnO (10 mM-30 min) substrates were capable of detecting 10⁻¹² M CV and 10⁻¹¹ M R6G aqueous solutions. The quantitative detection by the SERS substrate was investigated by constructing a linear corresponding calibration plot. The Ag/AgBr/ZnO SERS substrate was regenerated by a simple visible light driven photocatalytic process. A plausible Z-scheme visible light photocatalytic mechanism seems to account for the Ag-ZnO-AgBr system. This SERS substrate can be separated from the reaction easily, and the results indicated that the film was reusable for eight times without significantly losing the SERS efficiency, each time accompanied by a simple photo-driven regeneration. This study reveals that the Ag/AgBr/ZnO film on glass is practically applicable as an ultra-highly sensitive SERS substrate that can be readily regenerated.

Zhengyi Zhang;Jiajie Yu;Liyun Ma;Yangshan Sun;Pingping Wang;Tianhe Wang;寿 彭

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

2020-1-5

Spatial distribution of highly energetic negative ions inherent in magnetron sputtering of oxides has long made low temperature deposition unsuitable for high quality films uniform over relatively large areas. Here we examine the distributions of structure as well as physical properties of magnetron sputtered Al-doped ZnO (AZO) films deposited at low temperatures (≤393 K) in which the bombardment from the negative oxygen ions was systematically studied by changing the discharge voltage (i.e., ion energy) and the substrate position (i.e., ion flux). The film structure was characterized by X-ray diffraction, Raman spectroscopy, and transmission electron microscopy; and the electrical and optical properties were obtained by a Hall system and Spectroscopic Ellipsometry. We found (i) that uniform yet high crystallite quality films can be obtained only when the energy of the negative ions was set below a threshold; (ii) that the ion flux exerted an ever-decreasing effect on modifying the film structure as the ion energy was reduced; and (iii) that a set of structural criteria, incorporating crystallite quality (orientations, size, lattice spacing) and point defects, were derived for low resistivity AZO films. The benefit of lowering the ion energy is then explained in terms of the favorable competition between radiation-induced defect generation and the subsequent dynamic annealing. These findings may pave a way for large-area coating of high quality AZO films at low temperatures.

Fanping Meng;寿 彭;Genbao Xu;Yun Wang;Fangfang Ge;Feng Huang

Thin Solid Films

2018-11-1

Abstract Double-textured ZnO:Al (AZO) transparent conducting films were prepared successfully by a novel method, including the process of deposition, etching and re-deposition. Only one-step etching process was adopted during the whole procedure, and NaOH solution (5 wt%) was employed as the etchant. Double-textured AZO films exhibited higher haze values when the working pressures of deposition and re-deposition process were different. Effective improvement of light trapping was obtained from the double-textured AZO films prepared by this method. For the double-textured AZO films, the resistivity kept the order of 10^-3 Ω cm. The double-textured AZO films prepared by the novel method, which can be used as front electrodes, have potential application in thin film solar cells for light trapping.

Ying Wang;Wanyu Ding;Hualin Wang;寿 彭;Yun Wang;Weiping Chai

Materials Letters

2015-6-15

Numerical modeling of conduction band offset (ΔE_C) between an n-type CdSO window layer and a p-type CdTe absorption layer on the effect of the cadmium telluride (CdTe) solar cells was studied through simulation. The simulation results show that a slightly positive ΔE_C yields high efficiency because the surface recombination rate at the CdSO/CdTe interface can be substantially reduced, leading to higher open-circuit voltage (V_OC) and fill factor. Further increase in ΔE_C (≥ 0.4 eV) will impose an energy barrier against the photo-generated electrons under forward bias. We demonstrated the mechanistic picture of this effect using thermionic emission. However, if intra-band tunneling is considered in the simulation, a large ΔE_C shows negligible influence on the performance of CdTe solar cells. Our simulation results suggest that an ΔE_C of 0.3 eV is an optimal conduction band offset for high-efficiency CdTe solar cells.

Yunfei Chen;Xuehai Tan;寿 彭;Cao Xin;Alan E. Delahoy;Ken K. Chin;Chuanjun Zhang

Journal of Electronic Materials

2018-2-1