Synthesis and electrical characteristics of Al/(p)PbS Schottky barrier junction

Nanocrystalline lead sulphide thin films are prepared by chemical bath deposition method at bath temperature 318 K using lead acetate and thiourea. The films deposited on the bare glass substrates are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Al/(p)PbS Schottky barrier junctions are fabricated on indium tin oxide (ITO) substrates to study the junction parameters. The current-voltage (I-V) characteristics of the junctions are measured in the temperature range 300-340 K and junction parameters are calculated. The ideality factor (n) and barrier height (ϕb) at different temperatures are found to vary from 5.628 to 4.810 and 0.780 eV to 0.792 eV, respectively. It is observed that the ideality factor decreases while the barrier height increases with increase of temperature. The discrepancy between the barrier height obtained from capacitance-voltage (C-V) and I-V characteristics is analysed. Further, it is found that the series resistance Rs of the junction are strongly temperature dependent. The carrier concentration determined from the capacitance-voltage (C-V) plot is found to be of the order 1016/cm3.