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

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 GaSe0.5Te0.5 nanoflakes. The GaSe0.5Te0.5 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 GaSe0.5Te0.5 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 GaSe0.5Te0.5 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 GaSe0.5Te0.5 nanoflakes hold extensive applications in next-generation photodetection and photosensing nanodevices.