Field emission enhancement from patterned gallium nitride nanowires

Patterned gallium nitride nanowires have been grown on n- Si( 100) substrates by pulsed laser ablation. The nanowires are patterned using a physical mask, resulting in regions of nanowire growth of different density. These gallium nitride nanowires are single- crystalline with hexagonal wurzite structures. The electrical transport measurements of individual GaN nanowires show near- linear current - voltage characteristics. The estimated electron densities of these individual GaN nanowires range from 1.8- 6.8 x 10(18) cm(-3). The field emission characteristics of these patterned gallium nitride nanowires show a turn- on field of 8.4 V mu m(-1) to achieve a current density of 0.01 mA cm(-2) and an enhanced field emission current density as high as 0.96 mA cm(-2) at an applied field of 10.8 V mu(-1). The field emission results indicate that, besides crystalline quality as well as the low electron affinity of gallium nitride, density difference in the nanowires growth greatly enhances their field emission properties by reducing the screening between nanowires.