Study of GaN-based light emitting diodes grown on chemical wet etching-patterned sapphire substrate with V-shaped pits roughening surfaces

Abstract—We investigate the mechanism responding for perfor-mance enhancement of gallium nitride (GaN)-based light-emitting diode (LED) grown on chemical wet-etching-patterned sapphire substrate (CWE-PSS) with V-Shaped pit features on the top surface. According to temperature-dependent photoluminescence (PL) measurement and the measured external quantum effi-ciency, the structure can simultaneously enhance both internal quantum efficiency and light extraction efficiency. Comparing to devices grown on planar sapphire substrate, the threading dislocation defects of LED grown on CWE-PSS are reduced from 1.28 10 cm to 3.62 10 cm, leading to a 12.5 % enhance-ment in internal quantum efficiency. In terms of the theoretical computing of radiation patterns, the V-Shaped pits roughening surface can be thought of as a strong diffuser with paraboloidal autocorrelation function, increasing the escape probability o