Enhancement-mode ZnO/Mg_0.5Zn_0.5O HFET on Si

Abstract

We report a bottom-gate and enhancement-mode ZnO/Mg0.5Zn0.5O heterojunction field effect transistor (HFET) on Si. This new heterostructure which is grown by using molecular beam epitaxy (MBE) reduces interface defects and traps. By tailoring Mg composition (x) in the MgxZn1−xO barrier layer up to 50%, the Mg0.5Zn0.5O exhibits insulating properties and the resultant HFET works in an enhancement mode with a field effective mobility of μFE = 21cm2 V−1 s−1, transconductance of gm = 44mSmm−1, on/off ratio of 1 × 105 and off current ~1.33 × 10−8 Amm−1. The device shows good ambient stability.