The characterization of nanostructured GaN prepared via low temperature photoelectrochemical etching at different etching period / Nur Iwani Nor Izaham ... [et al.]

This study investigates the nanostructured GaN prepared via low temperature direct current photoelectrochemical (DCPEC) etching with varying etching durations of 40 min and 55 min. One of the key challenges in optimizing DCPEC is managing the system's thermal stability. Operating at low temperatures is crucial to avoid the excessive heat transfer from the light source, which poses the risk of electrolyte vaporization. Such vaporization can disrupt the delicate balance of the DCPEC process, potentially leading to system instability, inefficient etching, or even failure. This work obtained substantial structural and optical characteristics of nanostructured GaN samples compared to as grown sample. This study ultilized 4% potassium hydroxide (KOH) electrolyte, 30 mA direct current (DC), and 100 W of ultraviolet (UV) light. The FESEM micrographs revealed that the pores have hexagonal shape and ridged structure. The nanostructured samples displayed a significant increase in photoluminescence (PL) intensity and a shift towards longer wavelengths in the band edge PL peaks, which can be attributed to the release of compressive stress. The Full with Half Minimum (FWHM) of the 40 min sample has the lowest value compared to the as grown and 55 min samples for symmetry omega scan, indicating a better crystalline quality of the sample.