Direction Dependent Electrical and Optical Properties of Gallium Nitride Nanowires

Gallium Nitride (GaN) nanowires are synthesized in two distinct directions the <10-10> a-direction and the <0001> c- direction using a direct nitridation scheme. Field effect transistors are then fabricated using the as-synthesized 'a' and 'c' direction nanowires. Gate dependent electrical transport measurements performed on the a-direction nanowires showed an increase in conductivity with the applied gate bias while no gate dependent conductivity is observed in the case of 'c' direction nanowires. The electron mobility for the a- direction GaN nanowire FETs is estimated to be 170 cm2/V- s .Photo luminescence (PL) and UV-Vis absorption spectroscopy measurements show that the band gap of nanowires grown in a- direction blue shifts by about 50-70 meV when compared to the wires grown in c- direction.