Aluminum top-gate ZnO nanowire transistors with improved transconductance

The authors shows that by replacing gold with aluminum for the top gate, the thickness of the gate dielectric increases by a few nanometers due to the spontaneous formation of an interfacial AlO_x layer. As a result, the Al top-gate FETs operate with gate currents below 1 pA for voltages up to 3 V, making them fully compatible with organic LEDs. The ZnO nanowires were grown hydrothermally on a zinc foil. Transmission electron microscopy (TEM) confirms that the nanowires grow along the c-axis and are single-crystalline. The as-grown nanowires are degenerately doped and require a post-growth anneal (600°C) to make them suitable for FETs.