Effect of substrate temperatures, deposition rate and heat treatment on structural and carrier transport mechanisms of thermal evaporated p-Cu₂S/n-CdS heterojunction

Abstract

The p-Cu₂S/n-CdS heterojunction (Hj) has been fabricated by vacuum deposition of p-Cu₂S thin film onto n-CdS thin film. CdS layer was evaporated at substrate temperature, Ts ≈ 473 K and rate of deposition ≈0.06 μm/min. The dark-temperature-current density-voltage (J-V-T) and illumination characteristics were measured over a reasonable temperature range (303-423K). The conduction mechanism was suggested to be thermo ionic for forward applied voltage < 0.2V. For higher voltage, the space charge limited current was the predominant mechanism. In the reverse direction, the generation and recombination mechanisms were the operating mechanisms. Finally, the photovoltaic characteristics and the spectral response of p-Cu₂S/n-CdS were also studied.