V‐shaped semipolar InGaN/GaN multi‐quantum‐well light‐emitting diodes directly grown on c‐plane patterned sapphire substrates

In this paper, we report growth of V-shaped GaN on c-plane patterned sapphire substrates (PSS) directly without any masks through a 3-dimensional (3D) growth. Furthermore, semipolar InGaN/GaN multi-quantum-well (MQW) LED is grown on the sidewalls of V-shaped GaN, with doubled the normal growth time of active region and p-type region. Through scanning electron microscopy (SEM) and cathodoluminescence (CL) test, two types of semipolar facets are found in V-pits, {1011} and {1122}, emitting at 446 and 393nm, respectively. In photoluminescence (PL), only one strong peak is observed at 441nm, which corresponds to {101} facets. In addition, two peaks at 448 and 500nm are observed in electroluminescence (EL) when injection current is low, which are attributed to {101} facets and c-plane, respectively. However, the peak from {101} facets becomes dominant with the increasing injection current from 3 to 100mA, whose wavelength has a blue-shift of only 2nm.