Effect of hydrazine hydrate concentration on structural, surface morphological and optoelectronic properties of SILAR deposited PbSe thin films

Lead Selenide (PbSe) thin films have been deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method to investigate the effect of hydrazine hydrate on film properties. The peak behavior of the X-ray diffractogram corroborates crystalline nature of PbSe thin films. The intensity of the major peaks attributable to PbSe improved at higher concentrations up to 5 ml HH and gets reduced for 7 ml HH. The average crystallite size is in the range 18.18-33.37 nm. The film surface of lower HH sample is composed of spherical grains which are arranged in a compact manner. On increasing HH some clusters appears on the surface of the film over a homogeneous background. The AFM micrographs show that the surfaces of the lead selenide thin films consist of dense distribution of nanoscale particles with a range of grain sizes. The roughness obtained is in the range 13.7-76.3 nm. Highly crystalline sample, 5HH exhibits very good topography. The direct band gap values are in the range 1.425-1.803 eV. Thus by varying HH we have been able to tune the band gaps over a wide range. The highly crystalline sample 5HH with least strain and excellent topography exhibits maximum conductivity.