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The in uence of thermal degradation and the interruption time on the optical characteristics of InGaN multi-quantum-well (MQW) structures was examined. A series of 5-period In0:08Ga0:92N/In0:02Ga0:98N MQW samples with di erent nal temperatures before cooling-down and with di erent interruption times during QW growth were grown on sapphire substrates by using metalorganic chemical vapor deposition. We carried out temperature-dependant photoluminescence (PL) and PL excitation measurements to elucidate the quantum eciency and the origin of the emission, respectively. From a comparison of PL spectra and luminescence eciency, we conclude that (1) high temperature ramping-up and exposure steps degrade the optical properties of QWs by thermal damage, (2) the InGaN QWs can be protected from thermal damage by a GaN capping layer, and (3) the interruption time during the QW growth somewhat degrades the optical properties of QWs.


The in uence of thermal degradation and the interruption time on the optical characteristics of InGaN multi-quantum-well (MQW) structures was examined. A series of 5-period In0:08Ga0:92N/In0:02Ga0:98N MQW samples with di erent nal temperatures before cooling-down and with di erent interruption times during QW growth were grown on sapphire substrates by using metalorganic chemical vapor deposition. We carried out temperature-dependant photoluminescence (PL) and PL excitation measurements to elucidate the quantum eciency and the origin of the emission, respectively. From a comparison of PL spectra and luminescence eciency, we conclude that (1) high temperature ramping-up and exposure steps degrade the optical properties of QWs by thermal damage, (2) the InGaN QWs can be protected from thermal damage by a GaN capping layer, and (3) the interruption time during the QW growth somewhat degrades the optical properties of QWs.