Electrical properties of ZnO nanowire field effect transistors with varying high- k Al₂O₃ dielectric thickness

We investigated the electronic properties of ZnO nanowire combined with the scaled high- k Al₂O₃ dielectrics using metal-oxide-semiconductor and field effect transistor (FET) device structures. We found that Al₂O₃ dielectric material can significantly reduce leakage currents when the applied voltage was restricted less than the transition voltage of direct tunneling to Fowler-Nordheim tunneling. The ZnO nanowire FETs with Al₂O₃ dielectrics exhibited the increase in electrical conductance, transconductance, and mobility and the threshold voltage shifted to the negative gate bias direction with decreasing Al₂O₃ dielectric layer thickness.