High-performance photodetectors based on bandgap engineered novel layer GaSe0.5Te0.5 nanoflakes

Abstract

Layered two-dimensional (2D) gallium monochalcogenide (GaX, X = S, Se, Te) semiconductor crystals hold great promise for potential electronics and photonics application. In this paper, we reported the optoelectronic properties of 2D bandgap engineered GaSe_0.5Te_0.5 nanoflakes. The GaSe_0.5Te_0.5 nanoflakes were synthesized by chemical vapor deposition (CVD) and characterized by XRD, SEM, TEM, XPS, Raman and PL spectra, which demonstrate the high crystal quality of as-prepared nanoflakes. The photodetector based on single GaSe_0.5Te_0.5 nanoflake shows fast response time, high reversibility and stability both in air and vacuum. The photo-responsivity is up to 22 A W⁻¹ under illumination of 532 nm light. More interesting, the GaSe_0.5Te_0.5 nanoflake photodetector demonstrate extended light response range, as compared with pure GaSe. The photo-responsivity is 13 A W⁻¹ for 650 nm red light. The present results suggest strongly that the bandgap engineered 2D GaSe_0.5Te_0.5 nanoflakes hold extensive applications in next-generation photodetection and photosensing nanodevices.