1. Fig. 3. Temperature dependence of normalized integrated PL intensity for InGaN MQW on GaN substrates grown at Tg of 740, 780 and 800 ℃.

2. Fig. 5. Temperature dependence of normalized integrated PL intensity for InGaN MQW on sapphire substrates grown at Tg of 720, 750 and 770 ℃. on sapphire substrates

3. Fig.4. Schematic in-plane energy band diagram for InGaN layer grown at (a) 740 ℃ and (b) 800 ℃. 在低溫高電流注入時，電洞 會因溫度變化造成載子濃度及 遷移率下降，使電洞在量子井 中的分佈不均，且電洞的遷移 率下降，電洞無法有效的注入 量子井中累積在靠近 p-GaN 的量 子井中，而量子井中電洞不足， 使電子會有溢流現象，導致內 部量子效率遽降。

4. Conclusions Tg from 740 to 800 ℃ ， found that measurement temperature dependence of the PL integral intensity for the InGaN MQW grown on free-standing GaN substrates is strongly influenced by Tg. The largest decreases both in energy and in intensity of the PL with increasing measurement temperature were observed for the sample grown at 800 ℃. Investigate the influence of TD density on optical properties of InGaN MQWs, we measured the temperature dependence of the PL from InGaN MQWs grown on the sapphire substrates (TDs108cm2). It became clear that growth temperature did not affect significant change to the PL properties of the MQWs on the sapphire substrates.

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