Influences of chemical and cadmium telluride thin film solar cell interfaced with titanium oxynitride bi-layer: characteristics study

Abstract The cadmium telluride (CdTe) thin film solar cells are familiar for energy applications due to their significant properties. However, recombination losses and carrier concentration limit the overall optical and electrical behaviour of the CdTe layer during the interface engineering of the contact layer. This study aims to investigate the impact of titanium oxynitride (TiON) bilayers on CdTe thin film solar cells prepared through thermal evaporation, analyzing their functional behaviour under varying TiON thicknesses of 0, 15, 30, and 45 nm at a deposition temperature of 500 °C. With thermal evaporation, TiON is uniformly distributed and exhibits a reduced crystalline structure. Based on the investigational result, the TiON layer with a thickness of 45 nm featuring CdTe provides the highest electrical conductivity of 3.5 × 10 −2 S/cm, reduced transmittance of 60 % at a wavelength of 900 nm, an improved bandgap of 1.67 eV, and a reduced refractive index of 2.5. The highest short-circuit current density of 27.2 mA/cm 2 and an open-circuit voltage of 0.739 V are achieved with a 45 nm TiON layer. Additionally, the impact of surface roughness contributes to a better scattering effect, with a maximum value of 65 % noted for the CdTe layer coated with 45 nm of TiON. This CdTe with a 45 nm TiON layer is a promising material for photovoltaic thin film applications.