InGaN/GaN disk-in-nanowire white light emitting diodes on (001) silicon

Abstract

High density (∼ 1011 cm-2) GaN nanowires and InGaN/GaN disk-in-nanowire heterostructures have been grown on (001) silicon substrates by plasma-assisted molecular beam epitaxy. The nanowires exhibit excellent uniformity in length and diameter and a broad emission is obtained by incorporating InGaN disks of varying composition along the length of the nanowires. Monolithic lighting emitting diodes were fabricated with appropriate n- and p-doping of contact layers. White light emission with chromaticity coordinates of x=0.29 and y=0.37 and a correlated color temperature of 5500-6500 K at an injection current of 50 A/ cm2 is measured. The measured external quantum efficiency of the devices do not exhibit any rollover (droop) up to an injection current density of 400 A/ cm2. © 2011 American Institute of Physics.