Metal–insulator transition in few-layered GaTe transistors

Two-dimensional (2D) materials have triggered enormous interest thanks to their interesting properties and potential applications, ranging from nanoelectronics to energy catalysis and biomedicals. In addition to other widely investigated 2D materials, GaTe, a layered material with a direct band gap of ~1.7 eV, is of importance for applications such as optoelectronics. However, detailed information on the transport properties of GaTe is yet to be explored, especially at low temperatures. Here, we report on electrical transport measurements on few-layered GaTe field effect transistors (FETs) encapsulated by h-BN at different temperatures. We find that by tuning the carrier density, ambipolar transport was realized in GaTe devices, and an electrical-field-induced metal to insulator transition (MIT) was observed when it was hole doped. The mobilities of GaTe devices show a clear dependence on temperature and increase with the decrease of temperature, reaching ~1200 cm2V−1s−1 at 3 K. Our findings may inspire further electronic studies in devices based on GaTe.