Abstract This paper reports that the GaN thin films with Ga-polarity and high quality were grown by radio-frequency molecular beam epitaxy on sapphire (0001) substrate with a double AlN buffer layer. The buffer layer consists of a high-temperature (HT) AlN layer and a low-temperature (LT) AlN layer grown at 800℃ and 600℃, respectively. It is demonstrated that the HT-AlN layer can result in the growth of GaN epilayer in Ga-polarity and the LT-AlN layer is helpful for the improvement of the epilayer quality. It is observed that the carrier mobility of the GaN epilayer increases from 458 to 858 cm$^{2}$/V$\cdot $s at room temperature when the thickness of LT-AlN layer varies from 0 to 20 nm. The full width at half maximum of x-ray rocking curves also demonstrates a substantial improvement in the quality of GaN epilayers by the utilization of LT-AlN layer.
Received: 07 February 2007
Revised: 30 August 2007
Accepted manuscript online:
(Molecular, atomic, ion, and chemical beam epitaxy)
Fund: Project supported by
the National Natural Science Foundation of China (Grant No
10574130).
Cite this article:
Li Xin-Hua(李新化), Zhong Fei(钟飞), Qiu Kai(邱凯), Yin Zhi-Jun(尹志军), and Ji Chang-Jian(姬长建) Effect of double AlN buffer layer on the qualities of GaN films grown by radio-frequency molecular beam epitaxy 2008 Chin. Phys. B 17 1360
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