Structural and Optical Analysis of (In, Ga)N Structures Grown by MOCVD

An X-ray and cathodoluminescence analysis of thick InGaN/GaN single layers and 10 × (InGaN/GaN) multiple quantum wells (MQWs) is presented. The layers were grown by low-pressure metal organic chemical vapor deposition (LP-MOCVD). The strain state and the In concentration in (InGaN/GaN) MQW systems are evaluated with the help of reciprocal space maps around the symmetric (0002) and asymmetric (101-5) Bragg reflections. Depending on the In incorporation, sublayer thickness and deposition parameters, the MQW system is either fully strained, partially relaxed, or exhibits phase decomposition effects. At 6 K the laterally integrated CL spectrum of the fully strained MQW shows a very efficient blue emission centered at 2.841 eV with a FWHM of 50 meV (σ = 21 meV). At room temperature the main emission is centered at 2.792 eV with an integral FWHM of 161 meV.