TEMPERATURE DEPENDENT SPECTRAL RESPONSE OF Al-DOPED Sn/(n)ZnO SCHOTTKY JUNCTION AND ITS PHOTOVOLTAIC PERFORMANCE
Thin film of Al doped Sn/(n)ZnO Schottky junctions were prepared by vacuum evaporation and studied their spectral response and photovoltaic behaviour under elevated temperature of the range 303-478 K. A significant improved spectral response of a typical junction was exhibited for λ<0.35μm and its maximum PV efficiency was found to 1.22％ with respect to the energy in a bandwidth of 0.25 μm≤λ≤0.80 μm at room temperature. The conversion efficiency was observed to an overall improvement up to 343 K. The increase of junction current as well as peak in spectral response with temperature is mainly due to increase of grain size and corresponding decrease of grain boundaries in the film. The maximum spectral sensitivity of the junction around 380 nm corresponds to an optical band gap of 3.26 eV which is very close to the band gap energy of stoichiometric ZnO(3.20 eV) film. However, its efficiency decreases with increase of temperatures beyond 343 K as its significant open circuit voltage (Voc) decreases. During the film deposition, large number of oxygen ions (O2) were chemisorbed and incorporated at the grain boundaries and also on the surface of the film producing potential barriers, which hinder the electrical transport. The decrease of junction current for longer wavelengths in the spectral response is usually explained on the basis of high transmittance of light (i.e. low absorbance) beyond 0.38 μm. The similar phenomena were also observed at room temperature by increasing heavily doped with Al content.
Fill factor PV efficiency Schottky junction Spectral response.
G Wary T Kachari A Rahman
Department of Physics Cotton College Guwahati -781001, India Department of Physics Gauhati University Guwahati-781014, India
国际会议
The Ninth Asian Thermophysical Properties Conference(第九届亚洲热物理性能会议 ATPC 2010)
北京
英文
248-253
2010-10-19（万方平台首次上网日期，不代表论文的发表时间）