Electron Transport Performance of Germanium Selenide and Germanium Sulfide Field-Effect-Transistors in Dual Gates Configuration

The layered Group-IV monochalcogenides, such as, Germanium Selenide (GeSe) and Germanium Sulfide (GeS) have recently attracted attention due to their optoelectronic properties and stability in ambient air. Here, we fabricate split-gate field effect transistors based on GeSe and GeS flakes were mechanically exfoliated, and transferred on the top of FET using aligned dry transfer technique. The Raman peaks of GeS were measured and compared to recent theoretical work, which have good agreement. GeSe Raman peaks were observed at 150, and 188 cm ^-1 . The electron transport performance of GeSe and GeS FETs were characterized and compared to other design configurations. The transfer characteristics of both GeSe, and GeS exhibit p-type semiconductor material. We show different field effect carrier mobility of our GeSe devices and GeS devices, which can be improved using different passivation methods. In addition, the device stability was measured and characterized for a period at least 38 days. Our results indicate that the performance of GeSe FET did not show any noticeable change, making these devices relatively resilient to air exposure. These GeSe and GeS FET can be key materials for the next generation of electronics.