Morphological, structural, and emission characterization of trench defects in InGaN/GaN quantum well structures

Abstract

Articles you may be interested inCorrelation between the structural and cathodoluminescence properties in InGaN/GaN multiple quantum wells with large number of quantum wells J. Vac. Sci. Technol. A 32, 051503 (2014); 10.1116/1.4889857 Correlations between the morphology and emission properties of trench defects in InGaN/GaN quantum wells J. Appl. Phys. 113, 073505 (2013); 10.1063/1.4792505 Morphological evolution of InGaN/GaN quantum-well heterostructures grown by metalorganic chemical vapor deposition Influence of strain-induced indium clustering on characteristics of InGaN/GaN multiple quantum wells with high indium composition

The impact of growth parameters on trench defects in InGaN/GaN quantum wells

“…a). This observation deviates from previous studies where emission at a longer wavelength only was observed . However, previous studies focussed mainly on blue‐emitting structures, typically grown at a temperature below 750 °C, which agrees with our data.…”

“…Nevertheless, III‐nitride materials suffer from a very high density of defects which might reduce the device efficiency. Besides the threading dislocations , which are extremely well‐known, trench defects occur at the surface of c ‐plane QW structures . This less‐studied defect, consists of a basal plane stacking fault (BSF) located in the QW stack and bounded by a vertical stacking mismatch boundary (SMB) which opens up into several pits thus forming a ditch at the surface of the structure .…”

“…This ditch has been shown to enclose a region of material with peculiar emission properties. The intensity of the emission may be higher or lower than that of the surrounding material, but in almost all cases reported to date the light is emitted at a longer wavelength . Additionally, the SMB itself is also believed to affect the emission, acting as a non‐radiative recombination centre .…”

Elimination of trench defects and V-pits from InGaN/GaN structures

“…1(b) and 1(d)) and may lead to the formation of a trench defect. 2,5 However, in many cases, we also observed that an SMB may be terminated by a subsequent BSF (Figs. 2(a)-2(d)), which extends to a different depth and also gives rise to another SMB ( Fig.…”

“…The formation of V-pits in InGaN layers may be caused by the opening of threading dislocations into inverted hexagonal pyramids terminated by the f10 11g planes. 1 The trench loops were first described as In inclusions; 3 however, detailed studies of these defects performed by Massabuau et al 2 elucidated the structure of the trench defects and revealed that at the base of such a defect, there is a basal stacking fault (BSF) terminated by a stacking mismatch boundary (SMB). In crosssection TEM studies, a trench defect looks like two V-pits separated by a BSF (Fig.…”