Quality and thermal stability of thin InGaN films

Laser diodes with InGaN quantum wells emitting at long wavelengths are required for the application in compact laser projection. However, quantum wells with indium contents higher than 20% show weak photoluminescence performance as a result of high defect densities. We analyzed the root causes of the low performance of such quantum wells in detail. The influence of the indium content, the annealing temperature and the barrier structure on the quantum-well stability was investigated. We found that quantum wells with indium contents higher than 20% degrade due to the diffusion of indium atoms. Vertical diffusion coefficients for different barrier materials are extracted.