GaN/AIN Multiple Quantum Wells Grown on GaN-AIN Waveguide Structure by Metalorganic Vapor-Phase Epitaxy

摘要

High-optical-confinement waveguide structure based on nitride semiconduc-tors is proposed and demonstrated for the first time with metal organic vapor-phase epitaxy.The waveguide structure composed of 1-mu m-thick A1N cladding layer,2-mu m-thick GaN guiding layer,and 40 periods of GaN/AIN multiple quantum wells (MQWs)was grown using optimized growth conditions for each layer.For improved material quality,the two-step growth technique using low-temperature A1N and GaN nucleation layers was utilized to reduce the stress induced by lattice mismatch between each layer.The high-optical-con-finement structure could therefore be grown with high quality,leading to a successful observation of inter-sub-band absorption in GaN/AIN MQWs.The inter-sub-band absorption wavelength observed in such structure is in good agreement with that of MQWs grown on GaN layer,showing that the proposed waveguide structure can be used as a standard structure for optical devices based on inter-sub-band absorption.