Electronic properties of germanane field-effect transistors

A new two dimensional (2D) material—germanane—has been synthesised recently with promising electrical and optical properties. In this paper we report the first realisation of germanane field-effect transistors fabricated from multilayer single crystal flakes. Our germanane devices show transport in both electron and hole doped regimes with on/off current ratio of up to 10⁵(10⁴) and carrier mobilities of 150 cm² (V · s)^-1(70 cm² (V · s)^-1) at 77~ K (room temperature). A significant enhancement of the device conductivity under illumination with 650~ nm red laser is observed. Our results reveal ambipolar transport properties of germanane with great potential for (opto)electronics applications.