Contact characteristics in GaN nanowire devices

Abstract

GaN nanowire field-effect transistors were fabricated using single-crystallineGaN nanowires synthesized by thermal evaporation of GaN powder withNH3. They were found to be depletion mode transistors with an electron concentration of∼107 cm−1, electron mobilityof 50 cm2 V−1 s−1, and on/offcurrent ratio of ∼102. Using the transmission line method, the resistivity of the GaNnanowires and specific contact resistivity were estimated to be7.8 × 10−2 Ω cm and 1.7 × 10−5 Ω cm2, respectively. The current transport at contacts was described by the thermionic emissionwith a barrier height of 68 meV. The contact characteristics were improved by supplyingexcess carriers in the nanowires. These results will enable GaN nanowires to be used inreliable nanoscale devices.