Nitride-based green light emitting diodes grown by temperature ramping

High-quality InGaN/GaN multiquantum well (MQW) light emitting diode (LED) multilayer structures were prepared by temperature ramping method during metal-organic chemical vapor deposition (MOCVD) growth. Two photoluminescent (PL) peaks, one originating from a quantum-well-sensitive emission and the other arising from InGaN quasi-wetting layer on GaN barrier surface, were both observed at room temperature. The observation of each high-order double crystal X-ray diffraction satellite peak indicates that the interface between InGaN well layer and GaN barrier layer did not degrade in response to an increase in the growth temperature of GaN barrier layers. With separate current injections of 20 and 160 mA, it was found that the output power reaches 2.2 and 8.9 mW, respectively. Furthermore, the reliability of the fabricated green LEDs prepared by the temperature ramping was shown later to be reasonably good as we had expected.