Spatially resolved luminescence properties of non- and semi-polar InGaN quantum wells on GaN microrods

Abstract

Spatially resolved emission properties of InGaN/GaN quantum wells on the facets of microrods are analyzed by means of photoluminescence and cathodoluminescence measurements. We observe strongly localized emissions of the non- and semi-polar InGaN quantum wells from the top part of the microrods, suggesting optical emitters of high efficiency. The quantum wells are characterized by transmission electron microscopy measurements with respect to their indium composition and thickness. Those wells oriented in non- and semi-polar directions possess high In concentrations as well as low internal polarization fields which makes these directions excellent candidates for InGaN quantum well emitters. These investigations show that the applied microrod growth concept is an effective method to realize high quality InGaN quantum wells on GaN facets oriented in non- and semi-polar directions which makes optoelectronic emitters in the green gap region feasible.