Investigation of optical properties of InGaN multiple quantum wells on free-standing GaN substrates grown by metalorganic vapor phase epitaxy

Growth temperature (Tg) dependence of optical properties of InGaN multiple quantum wells (MQWs) grown by metalorganic vapor phase epitaxy (MOVPE) has been investigated. It was found that considerably large decrease in photoluminescence (PL) intensity from InGaN MQWs was observed with increasing measurement temperature from 5 to 300 K, when free-standing GaN substrates were used as a substrate and Tg was 800 °C. On the other hand, in the case of sapphire substrates, temperature dependence of PL intensity from MQWs was not significantly changed by Tg. These results indicate that optical properties of InGaN MQWs can be affected by Tg on free-standing GaN substrates.