Composition dependent structural, electrical, and optical properties of p-type InSb thin film for homojunction device application

Abstract

A key component of IR detectors and sources is the indium antimonide, having a narrow direct band gap of 0.17eV. The present paper deals with the fabrication, structural, electrical, and optical properties of p-type indium antimonide thin films of about 300 nm thickness by thermal evaporation technique on ultrasonically cleaned glass substrates with different compositions having formula InxSb1-x. Hall measurement indicates that the asfabricated films were p-type, having a carrier concentration of 0.435 x1018to 1.590 x1018 cm-3 and mobility of 3.29 – 6.62 cm2 /V-s for the film thickness of 300 nm. The activation energy (Ea) was determined and found to be in the range of 0.710 – 0.518 eV from the measurement of electrical resistivity of thin films in the temperature ranges of 313 K - 363 K. X-ray diffraction studies revealed the diffraction peaks (111), (220), and (311) confirm the bulk and thin film formation of InSb polycrystalline materials. The grain size (D), dislocation density(δ), and Strain (ε) have been calculated using XRD data. The lattice parameter (a=b=c) was found to be 6.7074Å from the X-ray diffraction method (XRD). The surface morphology study of thin film through scanning electron microscope reveals the formation of nano-grains with grain size ranging between 7.63 nm to 26.32 nm and surface area of 672-1343 nm2 .