An electrical characterization of a hetero-junction nanowire (NW) PN diode (n-GaN NW/p-Si) formed by dielectrophoresis alignment

Abstract

This is a report on the electrical characterization of gallium nitride (GaN) nanowire (NW) p-n junction diodes. These diodes were formed by assembling n-GaN NWs on p-Si (10 0) substrates using alternating current (AC) dielectrophoresis (DEP). The AC DEP was optimized with a bias voltage of 15 Vp-p at a frequency of 1 kHz. The hetero-junction single GaN nanowire p-n diode (n-GaN NW/p-Si) showed well-defined current rectifying behavior with a forward voltage drop of 1.2-2.0 V at a current density of 10-60 A/cm(2). The GaN nanowire p-n diodes had a high parasite resistance in the range of > 470 k Omega. We observed that these high resistances were mostly the result of the metal contacts to the n-GaN NWs. We also found that these parasite resistances were reduced by the formation of an additional capping layer on the top of the n-GaN NW as well as high temperature annealing. (c) 2006 Elsevier B.V. All rights reserved.