The electrical properties of n-CdS/p-CdTe and n-ZnS/p-CdTe heterojunctions fabricated by a combination of SILAR and vacuum deposition techniques

The paper reports successful fabrication of CdS/CdTe and ZnS/CdTe heterojunctions by a combination of two different deposition techniques viz. successive ionic layer adsorption and reaction (SILAR) and conventional vacuum deposition. The SILAR deposited CdS and ZnS layers formed well adherent and stable heterojunctions with the vacuum deposited CdTe. The electrical characteristics of the heterojunctions were analyzed by thermionic emission model and Cheung's model. The ideality factor, series resistance, barrier height, space charge density and thickness of the depletion region were determined by rigorous I–V, J-V and C–V characterization. The barrier heights of the devices were found to be in the range of 0.8 eV–0.9 eV. The thickness of the depletion region was found to be 5.2 nm and 7.1 nm while the space charge density was found to be 3.6 × 10²² m⁻³ and 1.59 × 10²¹ m^-3, respectively, for CdS/CdTe and ZnS/CdTe heterojunctions.