Influence of substrate temperature on structural, morphological and electrical properties of PbSe film deposited by radio frequency sputtering

Abstract

PbSe films were prepared by radio frequency magnetron sputtering from PbSe slices target under different substrate temperatures (from room temperature to 300°C). The effect of substrate temperature on structural properties of PbSe thin film was investigated. The surface morphology and the crystal structure of film were determined using field emission scanning electron microscopy and X-ray diffractometry, respectively. It was found that the grain shape changed with substrate temperature. When the substrate temperature was below 250°C, most of the crystal grains were spherical in shape. For temperatures above 250°C, the grains transformed to triangle or prismatic ones. Meanwhile, with increasing substrate temperature, the preferential orientation of the film changed from (200) to (220). To figure out the intrinsic mechanisms for this behavior, the texture coefficient, as well as the comparison between surface energy and elastic strain energy was performed. At lower temperature, the film growth was determined by surface energy, which was replaced by strain energy at higher temperature. Therefore, the diversity of crystal structure and morphology of the films at different substrate temperatures occurred. Moreover, the electrical properties of the p-type PbSe films are also quite dependent on substrate temperature. With substrate temperature increased, the electrical resistivity decreased from 1.88 to 0.14Ωcm, while the carrier concentration increased from 1.74×1018 to 4.08×1019cm−3 as the mobility was enhanced from 0.54 to 2.21cm2/Vs.