Depleted Sb2S3 Thin Film Photoconductive Detectors with Fast Response Speed and High Polarization Sensitivity

Antimony sulfide (Sb2S3) with high absorption coefficient reveals great potential for photodetectors (PDs) in various fields of military and national economy. A new type of depleted Sb2S3 thin film photoconductive detector by using titanium dioxide (TiO2) interlayer with the structure of Au/(glass/TiO2:)Sb2S3/Au is designed. Compared with normal Au/Sb2S3/Au devices, the depleted Sb2S3 PDs obtain a higher switching ratio of 90, greatly enhancing responsivity and specific detectivity. Owing to the electric field of the depletion region, the response time significantly decreases from 23.2 to 0.6 ms. In addition, the anisotropic Sb2S3 film with [120] dominated horizontal orientation is suitable for polarized light detection. The peak-to-valley ratio of the depleted Sb2S3 PD reaches 1.3 at polarized light. The results and methods of this study are expected to expand the application of PDs based on Sb2S3 films.