Electrical and optical properties, of Ag-(p)CdTe-ITO structure

Ag-(p)CdTe-ITO heterojunctions were prepared by thermal evaporation under pressure 10(-5) torr. The p-type CdTe films, with acceptor concentration (3.85-5.20)x10(17)/cm(3), were obtained by mixing 4.9%Sb with CdTe powder. The junctions exhibited rectifying I-V characteristics. Saturation current density was calculated for dark and illuminated junctions and found to be (5.5-9.12)x10(-5) A/cm(2) and (1.37-7.50)x10-6A/cm(2), respectively. The ideality factor of a typical junction was found to be 4.75 in dark and 2.18 under illumination, at room temperature (296K). Also ideality factor was found to decrease with increase in temperature. The value of A* the effective Richardson constant of a typical junction was found to be 81 Acm(-2) K-2 and the value of barrier height was found to be 0.65 eV in dark which increased to 0.74 under illumination. The barrier height did not show significant change with the variation of temperature in the range 299-338K. The structure exhibited photovoltaic effect characterized by high series resistance. The maximum power output under 759 lux of illumination was found to be 2x10(-4)mW.