The deep trap levels of AlxGa1–xN films with x in the range from 0 to 0.15 grown on c-plane sapphire substrates using rf-plasma-assisted molecular-beam epitaxy were investigated by deep level transient spectroscopy measurements. Two distinct defect levels (denoted as Ei and Di) were observed. The origins of the Ei and the Di were associated with point defects such as N vacancies, and extended defects such as threading dislocations, respectively. Depending upon the x-value, the activation energy and capture cross-section for the Di defect ranged from 0.19 to 0.41eV and 1.1 x 10–15 to 6.6 x 10–15cm2, respectively. The trap energy levels of Di defects in AlxGa1–xN were calculated and the values were non-linear with Al content. The bowing parameter of AlxGa1–xN films was determined to be 1.22.

Deep Level Defects in Si-Doped AlxGa1–xN Films Grown by Molecular-Beam Epitaxy. Y.S.Park, C.J.Park, C.M.Park, J.H.Na, J.S.Oh, I.T.Yoon, H.Y.Cho, T.W.Kang, J.E.Oh: Applied Physics Letters, 2005, 86[15], 152109 (3pp)