Green light emission from InGaN multiple quantum wells grown on GaN pyramidal stripes using selective area epitaxy

Abstract

Selective area epitaxy has been used to grow pyramidal GaN stripes, followed by InGaN multiple quantum well (MQW) structures, in order to produce long-wavelength green light emission. Stripes oriented along ⟨112¯0⟩ produce smooth {11¯01} sidewall facets. The room-temperature optical properties are investigated by cathodoluminescence spectroscopy using a scanning electron microscope. MQWs grown in unmasked reference regions exhibit emission at 450 nm. The stripe sidewalls emit light with peak wavelength of 500 nm with consistent linewidth and intensity. The stripe ridge emits light with peak intensity at wavelength of ∼550 nm. Based on the spatial extent of the 550 nm emission, the ridge is estimated to be ∼250 nm wide. The large redshift is produced by the enhanced presence of indium species due to lateral vapor diffusion and surface migration in selective area epitaxy.

Selective area epitaxy of InGaN quantum well triangular microrings with a single type of sidewall facets

“…All these sidewall facets have an angle of $621 to the (0 0 0 1) plane and fall into the same family plane of {1 1 0 1} [17]. This identification is consistent with prior observations of {1 1 0 1} sidewalls for InGaN/GaN stripes oriented along the o1 1 2 04 direction [16]. In contrast, microrings with each edge parallel to the o1 1 0 04 direction in Fig.…”

“…Recently, we demonstrated SAE growth of pyramidal stripes and microring structures of GaN followed by InGaN quantum wells (QWs) [16,17]. Sidewall facets of the microrings fell into three families, {1 1 2 2} and {2 1 3 3} planes on inner sidewalls, and {1 1 0 1} on outer sidewalls.…”

Three‐dimensional GaN for semipolar light emitters

“…The structural properties of an InGaN/GaN MQW stack deposited on 3D GaN are strongly influenced by the specific geometry of the underlying structure [31]. First, the properties of a QW deposited on a several micrometer big GaN stripe with triangular crosssection featuring just f1101g facets will be reported.…”

Spectral features in different sized InGaN/GaN micropyramids

“…Generally, inhomogeneities in 3D-Structures can be explained by a coaction of different processes, namely lateral vapour diffusion (LVD) [17], migration from mask region (MMR) [17] and strain induced In-incorporation [18]. As the lattice constant increases with increasing In-content, the redistribution to energetically favourable positions on the pyramids becomes more favourable than the incorporation at the sidewalls.…”