Simulation Study On A Novel ZnO / AlSb Heterojunction Solar Cell

Zinc oxide is a wide gap direct semiconductor (3.4eV) with the structure of hexagonalwurezite, On usually, zinc oxide is a n type semiconductor because of intrinsic defects. AZO(ZnO doping with Al) thin films is a good ITO (indium tin oxide) substitute material withgood conductivity, lower resistivity and high light transmittance (nearly up to90%). ZnO canwidely used in solar cell window layer due to its non-toxic, easy to manufacture, materialabundance and low cost. AlSb is a direct band gap semiconductor material with the band gapof1.62eV, thus the ideal materials for solar spectrum absorption with the absorptioncoefficient of104~105cm-1for hetero-junction solar cells as absorber layer. The theoreticalconverse efficiency of the AlSb cell is as high as27%.In this thesis, a new type of model of n-ZnO/i-AlSb/p-AlSb thin film solar cell is firstpresented based on the analysis of ZnO and AlSb. The performance of the cell wassimulated by using of AMPS-1D (Analysis of Microelectronic and Photonic Structures). Theeffect of n/p compensating doping, i-AlSb layer thickness and interface states on the opencircuit voltage Voc, short-circuit current Jsc, fill factor FF and conversion efficiency Effof thesolar cell was explored. It is shown in the simulation that fill factor and conversion efficiencywere decreased rapidly with the interface state density, the mechanism of this change isstudied as well. It is found in the simulation that a conversion efficiency of about24.658%isobtained in the ideal case.