In this research, InAs thin films were prepared by chemical spray pyrolysis method at different substrate temperatures (250 °C, 280 °C, 310 °C), with fixing the molarity of solution to 0.035 M and the deposition time to 30 min. X-ray diffraction shows that the structure of InAs films were polycrystalline and the most intensity planes approximately 25°.2′ and 29°.1′ corresponding to (111) and (200) orientation respectively. Surface analysis by atomic force microscopy (AFM) showed that the morphology of the deposited films is nanostructured. Optical measurements were characterized by UV–vis spectroscopy showed that the transmittance and the energy gap of InAs films decreased with increasing the substrate temperature due to the decreasing in the density of state by quantum confinement. Electrical characteristics showed that InAs film has been a negative Hall coefficient (R_H) value which confirm that InAs is n-type semiconductor and has carrier’s concentration about 1.67 × 10¹¹ cm⁻³.