Spatial distribution of optical intensity of overgrown semi-polar (20-21) InGaN/GaN multiple quantum wells dominated by surface morphology

Abstract

Polarized optical emission has been widely reported in semi-polar emitters as a result of the separation of the topmost valance bands. Simultaneously, semi-polar emitters exhibit isotropy in the spatial distribution of optical intensity, which is attributed to the influence of the surface morphology and the configuration of the underlying templates for overgrowth. This paper reports that a peanut-like pattern of intensity distribution has been observed in the semi-polar (20-21) sample, where most of the emitted light is located in the [11-20] direction. Compared with the bottom air voids formed during overgrowth, it can be seen that surface morphology plays a dominant role in affecting the spatial distribution of the optical intensity of the overgrown semi-polar (20-21) sample. With different surface height deviations, the spatial pattern could be tuned from sideward emission to a rectangular-like pattern. These results will promote the development of polarized light sources with great potential in the application of near-eye displays.