中文摘要：

研究了采用MOCVD技术分别在100与500Torr反应室压力下生长的非故意掺杂GaN薄膜的光学与电学性能。研究表明,低压100Torr外延生长条件可以有效地降低Ga与NH3气相反应造成GaN薄膜的碳杂质沾污,从而抑制造成光致发光中黄光峰与蓝光峰的深受主的形成,所制备的材料表现出较好的光学性能。同时,不同生长压力下的GaN薄膜表现出相异的电学性能,即在500Torr下生长的样品通常表现出更高的载流子浓度（（4.6-6.4）×1016 cm-3）与更高的迁移率（446-561cm2/（V.s））,而100Torr下生长的样品通常表现为更低的载流子浓度（1.56-3.99）×1016 cm-3与更低迁移率（22.9-202cm2/（V.s））。

英文摘要：

The optical and electrical properties of unintentionally doped GaN films grown at 100 Torr and 500 Torr pressure respectively by MOCVD system were investigated. It is proved that low growth pressure of 100 Torr can effectively reduce the Carbon impurities in the GaN films to suppress the formation of deep acceptors which are the origin of yellow and blue light peaks in the photoluminescence measurement, and the GaN films fabricated under such conditions present better optical properties. Meantime, GaN films grown at different pressure show different electrical properties. The GaN films grown at 500 Torr usually have higher carrier concentration （（4.6-6.4）×1016 cm-3） and higher carrier mobility （446-561cm2/（V.s））, while the GaN films grown at 100 Torr usually have lower carrier concentration （1.56-3.99）×1016 cm-3 ）and lower carrier mobility（22.9-202cm2/（V.s））.