In this study, the epitaxial growth of the full-composition-graded Al_xGa_1-xN films has been demonstrated on the sapphire substrates by using metalorganic chemical vapor deposition (MOCVD). The aluminum composition in the Al_xGa_1-xN films has been precisely controlled from 0 to 100%, as confirmed by X-ray diffraction and energy-dispersive spectroscopy analyses. The pseudo-periodic Al_xGa_1-xN/Al_yGa_1-yN structures are spontaneously formed during the initial growth of the graded AlGaN layer, which facilitate the strain relaxation. In addition, the behavior of the bending dislocations has been investigated in detail, and the threading dislocation bending along the growth direction is noted to relax the strain further.

在这项研究中，已通过使用金属有机化学气相沉积（MOCVD）在蓝宝石衬底上证明了全成分渐变Al _x Ga _1-x N膜的外延生长。X射线衍射和能量色散光谱分析证实，Al _x Ga _1-x N膜中的铝成分已精确控制在0％至100％之间。准周期Al _x Ga _1-x N / Al _y Ga _1-y在渐变AlGaN层的初始生长过程中会自发形成N结构，这有助于应变松弛。另外，已经对弯曲位错的行为进行了详细研究，并且注意到沿生长方向弯曲的螺纹位错进一步松弛了应变。