Study on GaN-based light emitting diodes grown on 4-in. Si (111) substrate

GaN-based light emitting diodes (LEDs) grown on 4-in. Si (111) substrate by metal-organic chemical vapor deposition have been systematically characterized. The significantly smooth surface of the sample has been confirmed by an atomic force microscope. In X-ray diffraction measurement, two kinds of fringe peaks were observed, which are believed to originate from the strained-layer superlattice (SLS) and multiple quantum wells. Moreover, from cross-sectional scanning electron microscope images of the sample, it is found that the interfaces of SLS are smooth. The 100-pair AlN/GaN SLS can be employed to modulate the strain between the GaN layer and substrate, resulting in the improvement of GaN crystalline quality. The full width at half maximum of omega-scan of the GaN (0002) diffraction is around 630 ''. In addition, the device properties have been investigated in detail, and the maximum light output power can reach 2.02 mW with a high saturation injection current of 320 mA. (C) 2014 Elsevier B.V. All rights reserved.