A fluorine based plasma surface modification process opens up a new avenue to improve the film conductivity and optoelectronic properties of Sb_2Se_3 broadband photodetector

摘要

Antimony selenide (Sb2Se3) emerges with great potential for broad-spectrum photonics due to the moderate band gap and excellent optical properties. However, the undesirable bulk electrical conductivity of Sb2Se3 drags down the carriers transport through the film and limits the device performance. To counter this challenge, herein, a ground-breaking surface technique based on fluorine plasma is applied on the Sb2Se3 films and analyzes through binding energy properties, morphologies and sheet resistances. F plasma modification is found to provide an obvious improvement of the conductivity of Sb2Se3 film, as a result of the suppressed Se vacancy. Moreover, we investigate the performance of Sb2Se3 thin film photodetector with F modification for the first time. The device presents a broad spectral photo-response ranging from visible to near-infrared region (500-1050 nm). Owing to the improved conductivity of Sb2Se3 film, the photodetector achieves a competitive responsivity of 35.42 A W-1, a high detectivity of 4.89 x 10(11) Jones, a ultrahigh external quantum efficiency of 5.06 x 10(3)% and a fast rise and decay time of 21.4 and 22.1 ms, achieving an obvious improvement as compared with the pristine device. This breakthrough opens up a new route to improve the conductivity of Sb2Se3 film and develop high-performance Sb2Se3 film photodetector devices.