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 x (InGaN/GaN) multiple quantum wells (MQWs) is presented. The layers were grown by low-pressure metal organic chemical vapor deposition (LP-MOC VD). The strain state and the In concentration in (InGaN/GaN) MQW systems a re evaluated with the help of reciprocal space maps around the symmetric (0 002) and asymmetric (10 (1) over cap 5) Bragg reflections. Depending on the In incorporation, sublayer thickness and deposition parameters, the MQW sy stem is either fully strained, partially relaxed, or exhibits phase decompo sition effects. At 6K the laterally integrated CL spectrum of the fully str ained MQW shows a very efficient blue emission centered at 2.841 eV with a FWHM of 50 meV (sigma = 21 meV). At room temperature the main emission is c entered at 2.792 eV with an integral FWHM of 161 meV.