ZnO metal-semiconductor field-effect transistors with Ag-Schottky gates

Metal-semiconductor field-effect transistors (MESFETs) were fabricated by reactive dc sputtering of Ag-Schottky gate contacts on ZnO thin-film channels grown by pulsed-laser deposition on sapphire. The n-type conductivity (normally on) of typical MESFETs is tunable over 8 decades in a voltage range of 2.5 V with an off voltage of -1.5 V and very low off-current density in the range of 10(-6) A/cm(2). Channel mobilities of up to 27 cm(2)/V s have been achieved. (C) 2008 American Institute of Physics.