Enhancement-mode ZnO/Mg0.5Zn0.5O HFET on Si

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 mu FE = 21 cm(2)V(-1)s(-1), transconductance of g(m) = 44 mS mm(-1), on/off ratio of 1 x 10(5) and off current similar to 1.33 x 10(-8)A mm(-1). The device shows good ambient stability.