Absorption, photocurrent, and infrared reflectivity spectra of the polycrystalline &bgr;‐FeSi2thin films in relation to the Si substrate temperature are presented. The photocurrent spectra involving both the fundamental interband, extrinsic defect transitions of &bgr;‐FeSi2and the intrinsic transitions of Si substrates are observed. Both the absorption and photocurrent measurements show the direct gap nature. A simple recombination model is proposed to account for the photocurrent results. We show that better quality &bgr;‐FeSi2films can be achieved at higher substrate temperature. The simplicity, sensitivity, and reliability of the photocurrent measurements for studying &bgr;‐FeSi2are well demonstrated. ©1995 American Institute of Physics.