Current Photovoltaic Research ISSN:2288-3274(Print) 2508-125X(Online)

ZnSe/Zn₃P₂ heterojunctions with a substrate configuration were fabricated using a series of cost-effective processes. Thin films of ZnTe and Zn₃P₂ were successively grown by close-spaced sublimation onto Mo-coated glass substrates. ZnSe layers thinner than 100nm were formed by annealing the Zn₃P₂ films in selenium vapor. Surface selenization generated a high density of micro-cracks which, along with voids, provided shunt paths and severely deteriorated the diode characteristics. Annealing the Zn₃P₂ film at 300ºC in a ZnCl₂ atmosphere before surface selenization produced a dense microstructure and prevented micro-crack generation. The mechanism of micro-crack generation by the selenization was described and the suppression effect of ZnCl₂ treatment on the micro-crack generation was explained. ZnSe/Zn₃P₂ heterojunctions with low leakage current (J₀ < 1 µA/cm² ) were obtained using an optimized surface selenization process with ZnCl₂ treatment. However, the series resistance was very high due to the presence of an electrical barrier between the ZnTe and Zn3P2 layers.