Metalorganic Vapor Phase Epitaxy of Semipolar InGaN Quantum Dots Based on GaN V‐shaped Pits

Semipolar {101 over bar 1} InGaN quantum dots (QDs) formed on GaN V-shaped pits by metal-organic vapor-phase epitaxy (MOVPE) with a growth interruption method are reported. The 3D GaN V-pit structures are directly grown on a patterned sapphire substrate (PSS). By adjusting the pattern arrangement direction on the substrate, it is observed in the scanning electron microscopy (SEM) image that elliptical QDs are formed on the {101 over bar 1} semipolar sidewalls of the V-pits with a density of about 5 x 10(10) cm(-2). The emission wavelength of semipolar InGaN QDs is confirmed by cathodoluminescence (CL). The gradient distribution of In composition and QD size are observed along the sidewall of the V-pits. On this basis, a three-period semipolar InGaN QD sample is prepared. For the temperature-dependent photoluminescence (TDPL) test, the prominent peak of the sample shows a blueshift with the increase in temperature and reaches the green band (approximate to 523 nm) at room temperature (RT). According to time-resolved photoluminescence (TRPL) decay curves, a carrier lifetime of 329.3 ps fit by the stretched exponential model is obtained at RT. Compared with c-plane QDs with the same growth method, the semipolar QDs have a shorter radiative recombination lifetime due to suppressed polarization electric field.