ZnSe and Cd0.6 Zn0.4Te for isotype heterojunction (IHJ) for photovoltaic applications

Abstract

Thin films of ZnSe, Cd₀.₆Zn₀.₄Te, and Cd₀.₆Zn₀.₄Te/ZnSe were thermally deposited on glass and silicon substrates. XRD results confirm that the films are nanocrystalline and have a cubic structure. Linear and nonlinear optical properties of the films were assessed. The evaluated optical band gap (E_g) values for ZnSe, Cd₀.₆Zn₀.₄Te, and ZnSe/Cd₀.₆Zn₀.₄Te films were 2.95, 1.71, and 1.757 eV, respectively. The electrical study evaluated I-V characteristics, rectification ratios, series and shunt resistance, ideality factor, and barrier height for ZnSe/p-Si, Cd₀.₆Zn₀.₄Te/p-Si heterojunctions, and n-Cd₀.₆Zn₀.₄Te/n-ZnSe isotype junctions at various temperatures. The ideality factor and barrier height results showed that the Cd₀.₆Zn₀.₄Te/p-Si device outperformed the ZnSe/p-Si device in terms of electrical conductivity as temperature increased. The novelty in this study is that the fabrication of the n-ZnSe/n-Cd_0.6Zn_0.4Te isotype junction has a higher current value by about 3 orders of magnitude than the constructions of ZnSe/p-Si and Cd_0.6Zn_0.4Te/p-Si heterojunctions. Furthermore, the significant decrement in its electrical parameters causes an enhancement in its electrical conductivity compared with other formed heterojunctions at room temperature.