Electrical characteristics of (n)Si/(p)PbS heterojunction prepared by chemical bath deposition technique

Abstract

Zn doped nanocrystalline PbS thin films is deposited on single crystal (n)-Si substrate by chemical bath deposition to form (n)Si/(p)PbS heterojunction structure. In order to study the current transport mechanism in (n)Si/(p)PbS heterojunction, the forward current–voltage characteristics is measured within the temperature 300 K – 340 K and capacitance–voltage characteristics is measured at a frequency of 1 kHz at 300 K. The forward current is greatly enhanced with increasing temperature whereas the reverse current is increased nominally. Junction parameters such as ideality factors, barrier heights, saturation current density, Richardson constant, etc. are determined from the I–V characteristics. The ideality factors are found to decrease with increase in temperature. The J–V characteristics under illumination showed poor photovoltaic effect of the junction. The higher value of ideality factor and poor photovoltaic conversion efficiency are due to the presence of interfacial layer, large series resistance and high defect density.