Effects of InGaN-interlayer on closed stripes of GaN grown by serpentine channel patterned sapphire substrate

Gallium nitride (GaN) is a widely investigated semiconductor owing to its fascinating features suitable for a plethora of optoelectronic applications; nevertheless, high-quality growth of this material remains a challenge. In this work, the crystal quality of GaN grown by serpentine channel patterned sapphire substrates (SCPSS) is improved via introducing indium gallium nitride (InGaN) as an interlayer (IL). The closed stripes of GaN are grown by the modified design of SCPSS. Our results show that the crystal quality of GaN grown in the form of closed stripes is superior than conventionally grown counterpart. Transmission electron microscopy (TEM) revealed that the design of SCPSS controls all threading dislocations (TDs) while cathodoluminescence (CL) analysis showed that the closed stripes are relaxed and produce many TDs. Therefore, further control over the TDs was achieved by InGaN-IL. During the growth process, the temperature of GaN was reduced and 20 nm thick InGaN-IL was added at 800 ° C . The detailed characterization of our developed samples indicated that the additional use of InGaN-IL in SCPSS is very effective for improving the crystal quality of GaN. We anticipate that our findings will improve the current understanding about the growth of high-quality GaN towards efficient optoelectronic devices.