Fabrication and properties of semi-polar (1-101) and (11-22) InGaN/GaN light emitting diodes on patterned Si substrates

InGaN/GaN light emitting diodes (LEDs) were fabricated on semi-polar (1-101) and (11-22) GaN templates which had been grown on patterned (001) and (113)Si substrates, respectively. The GaN templates were of 300 x 300 μm ² discs formed by the coalescence of GaN stripes grown by selective MOVPE method. The n-type electrode was fabricated on the back surface of the Si substrate. The electroluminescence (EL) peaks were observed around 440 nm and 420 nm in (1-101) and (11-22) LEDs, respectively. The full width at half maximum (FWHM) of the peaks at 20 mA were 33 nm ((1-101) LED) and 21 nm ((11-22) LED). The emission peak was slightly blue-shifted at high drive currents, which was smaller than that of conventional c-plane LEDs. The turn-on voltage of the diodes was of the order of 3-4 V.