Impact Of Doping And Diameter On The Electrical Properties Of Gasb Nanowires

The effect of doping and diameter on the electrical properties of vapor-liquid-solid grown GaSb nanowires was characterized using long channel back-gated lateral transistors and top-gated devices. The measurements showed that increasing the doping concentration significantly increases the conductivity while reducing the control over the channel potential and shifting the threshold voltage, as expected. The highest average mobility was 85 cm(2)/V.s measured for an unintentionally doped GaSb nanowire with a diameter of 45 nm, whereas medium doped nanowires with large diameters (81 nm) showed a value of 153 cm(2)/V.s. The mobility is found to be independent of nanowire diameter in the range of 36 nm-68 nm, while the resistivity is strongly reduced with increasing diameter attributed to the surface depletion of charge carriers. The data are in good agreement with an analytical calculation of the depletion depth. A high transconductance was achieved by scaling down the channel length to 200 nm, reaching a maximum value of 80 mu S/mu m for a top-gated GaSb nanowires transistor with an ON-resistance of 26 k Omega corresponding to 3.9 Omega.mm. The lowest contact resistance obtained was 0.35 Omega.mm for transistors with the highest doping concentration. Published by AIP Publishing.