Phosphor-free white emission from InGaN quantum wells grown on in situ formed submicron-scale multifaceted GaN stripes

摘要

We demonstrate in situ self-organization of multifaceted GaN stripes on m-sapphire substrates. The GaN stripes aligned along (11)over bar23 with submicron-scale {11 (2) over bar2}, {10 (1) over bar1}, {20 (2) over bar1}, {11 (2) over bar4}, and {0001} facets are identified and employed as growth templates of InGaN quantum wells (QWs). Under identical growth conditions the emission spectrum of the InGaN QWs is determined by the GaN stripe shaping and atomic structures of the stripe surface. For instance, the growth rate (thickness) of the InGaN QWs is proportional to the layer spacing and dangling bond density of specific growth face and plays a key role in emission wavelength. Accordingly, using the stripe templates the InGaN QWs on different stripe facets have different emission wavelengths. Broad photoluminescence peak covering ultraviolet, blue, green, yellow, amber, and red emissions is observed for the InGaN QWs grown on various sidewall facets of the stripe templates. The chromaticity diagram indicates a cool-daylight white emission with a correlated color temperature of 5997 K. (C) 2018 Published by Elsevier B.V.