Near ultraviolet InGaN/GaN MQWs grown on maskless periodically grooved sapphire substrates fabricated by wet chemical etching

In the paper, we describe the fabrication and characteristics of near ultraviolet InGaN/GaN multiple quantum wells (MQWs) grown on maskless periodically grooved sapphire, which was obtained by wet chemical etching. Hot acid etching combining with atomic force microscopy (AFM), transmission electron microscopy (TEM) were adopted to characterize the films quality. Compared with the MQWs grown on planar sapphire, the sample grown on grooved sapphire fabricated by wet chemical etching shows better crystalline quality, remarkable reduction of threading dislocations was achieved. Meanwhile, the sample grown on grooved sapphire shows more than three times larger electroluminescence (EL) intensity than the sample on planar substrate. The results show the method grown on grooved sapphire fabricated by wet chemical etching can very effectively reduce threading dislocations and get better films quality with higher optical properties.