Band-gap states and quality analyses of AlGaN/GaN hetero-structures

在传统的MOCVD生长的AlGaN/GaN异质结中，在1120~1170℃范围内，随着GaN缓冲层生长温度的降低，C杂质的掺入增加。同时，深能级缺陷在导带下方的2.07、2.80和3.23 eV处变得密集，这可能是由于GaN缓冲层中的Ga空位和浅C受主所致。其中，2.80 eV和3.23 eV能级是造成AlGaN/GaN异质结载流子俘获现象的主要原因。

In conventional AlGaN/GaN hetero-structures grown by MOCVD, the C impurity incorporation was enhanced with decreasing the growth temperature of the GaN buffer layer between 1120 and 1170℃. Concurrently, deep-level defects became dense at2.07, 2.80, and 3.23eV below the conduction band, presumably attributable to Ga vacancies and shallow C acceptors in the GaN buffer layer. Among them, the 2.80 and 3.23eV levels are found to be strongly responsible for the carrier-trapping phenomena in the AlGaN/GaN hetero-structures.