Bandgap opening in layered gray arsenic alloy

Abstract

As an essential member of group-V layered materials, gray arsenic (g-As) has recently begun to draw researchers’ attention due to fantastic physical properties predicted by theoretical calculation. However, g-As presents semimetal behavior as the thickness exceeds bilayers, which hinders its further device applications, such as in logic electronics. Herein, we report the growth of high quality gray arsenic-phosphorus-tin (g-AsPSn) alloys via a simple one-step chemical vapor transport process. The as-grown g-AsPSn alloy remains the same layered rhombohedral structure as g-As, while the g-AsPSn alloy shows an opened bandgap compared with g-As. Infrared absorption and photoluminescence spectra reveal a narrow optical bandgap of 0.2 eV. A field effect transistor based on few-layer g-AsPSn alloy flakes shows a typical p-type semiconductor behavior and a relatively high mobility of ∼66 cm2 V−1 S−1 under ambient conditions. It can be envisioned that the synthesized two-dimensional layered narrow-gap g-AsPSn alloy presents considerable potential applications in electronics and infrared optoelectronics.