Infrared reflection of GaN and AlGaN thin film heterostructures with AlN buffer layers
نویسندگان
چکیده
Infrared reflection spectroscopy is applied to state-of-the-art thin film heterostructures of group-III nitrides on sapphire and Si substrates. The individual layers of GaN and AlGaN and the AlN buffer layer are identified by their phonon frequencies. Under non-perpendicular incidence of the light, A1~LO! phonon modes are observed in the wurtzite system. The presence of the very thin AlN buffer layer manifests itself in clear features of the AlN phonons. The A1~LO! phonon mode energy is determined in AlxGa12xN for x'0.15. Raman spectra confirm our findings. © 1996 American Institute of Physics. @S0003-6951~96!01118-4#
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تاریخ انتشار 1996