Several processes participating in a decrease and the droop of external quantum efficiency in green InGaN/GaN MQW structures

The obtained experimental results allow us to clarify the nature of mechanisms related to the presence of cations in disordered InGaN alloy and hetero-interfaces. The capture of charge carriers by cations reduces the external quantum efficiency (EQE) in green MQWs at j < 10 A/cm2. The EQE droop phenomenon caused by smoothed out lateral potential fluctuations occurs at j > 10 A/cm2. At j > 40 A/cm2 the droop associated with interactions between charge carriers and dislocations and grain boundaries takes place.

InN on GaN Heterostructure Growth by Migration Enhanced Epitaxial Afterglow (MEAglow)

ABSTRACTIn this paper we discuss the formation of InN on GaN heterostructures. Film growth was accomplished using a new method coined Migration Enhanced Epitaxial Afterglow (MEAglow), an improved form of pulsed delivery Plasma Enhanced Chemical Vapour Deposition (PECVD) [1]. Initial x-ray diffraction (XRD) analysis results indicated that an InGaN alloy layer formed under the InN during growth. No GaN was seen from the original buffer layer. It was postulated that indium metal deposited prior to complete nitridation diffused into the relatively thin GaN layer producing InGaN. To verify the integrity of the insulating GaN layer, a third party GaN substrate was substituted. Results were unchanged. Parameters were then modified to reduce the amount of indium used for the initial metal deposition. XRD results indicated a sharper interface between the semi-insulating GaN and conductive InN layer. Hall Effect measurements are included. We’ve shown that the growth of a device suitable heterostructure is possible using the MEAglow technique.