Improving carrier transport and light emission in a silicon-nanocrystal based MOS light-emitting diode on silicon nanopillar array

A silicon-nanocrystal (nc-Si) based metal-oxide-semiconductor light-emitting diode (MOSLED) on Si nanopillar array with size, height, and density of 30 nm, 350 nm, and 2.8x10(10) cm(-2), respectively, is characterized. The nanopillar roughened Si surface contributes to the improved turn-on characteristics by enhancing Fowler-Nordheim tunneling and reducing effective barrier height, providing the MOSLED a maximum optical power of 0.7 mu W obtained at biased current of 375 mu A. The optical intensity, turn-on current, and power-current slope of nc-Si MOSLED on high-aspect-ratio Si nanopillar array are 140 mu W/cm(2), 5 mu A, 2 +/- 0.8 mW/A, respectively. A maximum external quantum efficiency of 0.1% is reported.