Cobalt Tungsten Oxide Thin Films Prepared by RF‐Sputter for Photosensor

This study reports the synthesis and characterization of nonstoichiometric nanocrystalline Co_2.59W_0.41O₄ thin film by the radio frequency (RF)‐sputter technique suitable for photosensor applications. The photoconductive characteristics of Co_2.59W_0.41O₄ thin film are investigated by fabricating a sandwich‐structure device of p⁺Si/Co_2.59W_0.41O₄ thin film/indium tin oxide with Schottky barriers. The device characteristics including responsivity, light intensity response, and time response are studied. It is found that Co_2.59W_0.41O₄ thin film exhibits good absorption (absorption coefficient ≈10⁴ cm⁻¹ in visible light spectrum), relatively high responsivity (R_res = 5.427 A W⁻¹), and fast photoresponse time including rise time (t_r) = 81.04 ms and fall time (t_f) = 80.67 ms. Hence, the Co_2.59W_0.41O₄ thin film is favorable for potential photosensor applications.