The effect of gate control on the electrical conductivity of InAs nanowires

Semiconductor nanowires are an interesting step on the road to zero-dimensional systems. InAs is an especially suitable material because ohmic contacts can be prepared straightforwardly. Provided sufficient gate control, quantum dots can be formed. Here, the electronic transport properties of nominally undoped InAs nanowires grown by metal-organic vapour phase epitaxy are examined. Their typical length and diameter are 5 μm and 100 nm, respectively. The gate control is studied for different gate geometries, e. g. fingers, back- and top-gates. Furthermore, we compare the performance of high-k dielectrics, e. g. GdScO3 or LaLuO3, with standard dielectrics like SiO2 or Si3N4. Four-terminal transport measurements are performed both at room temperature as well as at low temperatures down to 30 mK. Field effect transistor measurements performed at room temperature show that by using high-k dielectrics, the Ion/Ioff ratio can be improved by at least one order of magnitude.