Photoresponse in sequentially stacked antimony selenide thin films

Abstract

Antimony selenide (Sb _2 Se _3 ), a binary semiconducting compound has widespread research attention due to its excellent optoelectronic properties in the visible region and usefulness in applications such as solar cells, photosensors and photoelectrodes. The presented study explores the thickness dependent photoresponse in Sb _2 Se _3 thin films, prepared by reactive selenization of antimony films having thickness values of ∼938 nm and ∼1879 nm when stacked second time. Growth orientation along [001] direction was achieved through carefully optimized selenization conditions to enable favourable charge transport in anisotropic Sb _2 Se _3 . Predominant Sb _2 Se _3 formation was inferred from x-ray diffraction, Raman spectroscopy, secondary electron microscopy and energy-dispersive X-ray analyses. High optical absorption coefficient values of about 1 × 10 ^5 cm ^−1 and 5.7 × 10 ^4 cm ^−1 were observed for ∼938 nm and ∼1879 nm thick Sb _2 Se _3 thin films. Further, the optoelectronic properties were elucidated through current–voltage and transient photoresponse measurements under dark and illumination conditions. The measurements were done under zero and different bias voltages. Sb _2 Se _3 films having∼ 938 nm thickness exhibited self-driven photoresponse with a responsivity of 4.3×10 ^−8 A W ^−1 and detectivity of 3.5 × 10 ^6 jones respectively, under AM 1.5 G illumination conditions.

Keywords

• Sb2Se3 thin films
• selenization
• photoresponse