Effect of annealing treatment on electroluminescence from GaN/Si nanoheterostructure array.

A GaN/Si nanoheterostructure array was prepared by growing GaN nanostructures on silicon nanoporous pillar array (Si-NPA). Based on as-grown and annealed GaN/Si-NPA, two light-emitting diodes (LEDs) were fabricated. It was found that after the annealing treatment, both the turn-on voltage and the leakage current density of the nanoheterostructure varied greatly, together with the electroluminescence (EL) changed from a yellow band to a near infrared band. The EL variation was attributed to the radiative transition being transformed from a defect-related recombination in GaN to an interfacial recombination of GaN/Si-NPA. Ours might have provided an effective approach for fabricating GaN/Si-based LEDs with different emission wavelengths.