Influence of high temperature AIN buffer on optical gain in AIGaN/AIGaN multiple quantum well structures

摘要

Standard stripe-length dependent optical-pumping measurements have been performed on AlGaN/ AlGaN multiple quantum wells (MQWs) on an AIN buffer grown using two different kinds of technologies, I.e., "GaN interlayer" and "porous AIN buffer." The net modal gains of the two samples along both m- and a-axis have been obtained, showing that the net modal gain of the MQWs on the AIN grown using "GaN interlayer" is higher than that on the AIN grown using "porous AIN buffer." Reciprocal space mapping measurements have indicated that the MQW structure on the AIN structure grown using "GaN interlayer" is fully strained while that on the AIN grown using "porous AIN buffer" is partially strain-relaxed. The net modal gain along the m-axis is higher than that along the a-axis in both samples, highly reasonably indicating that the most favourable orientation for forming the cavity facets is not (11-20) direction of c-plane sapphire, along which Ill-nitride on c-plane sapphire is normally cleaved.