The optical properties of Al _x Ga_1−x N-based quantum wells (QWs) with various thicknesses are investigated. When the Al _x Ga_1−x N thickness in Al_0.8Ga_0.2N/AlN QWs exceeds 6 nm, the photoluminescence lifetime is drastically shortened even at cryogenic temperatures, which indicates that nonradiative recombination processes are enhanced. Interestingly, the thicknesses for the degradation of the optical properties of Al _x Ga_1−x N on AlN (0001) are about two orders of magnitude thinner than the critical layer thicknesses for lattice relaxation determined by a conventional X-ray diffraction method. To avoid the degradation of the QW optical properties, Al _y Ga_1−y N (y > x) underlying layers are effective.

研究了具有不同厚度的 Al _x Ga _{1- x} N 基量子阱 (QW)的光学特性。当Al _0.8 Ga _0.2 N/AlN QWs 中的Al _x Ga _{1- x} N 厚度超过6 nm 时，即使在低温下，光致发光寿命也会急剧缩短，这表明非辐射复合过程得到增强。有趣的是，Al _x Ga _{1− x}光学性能退化的厚度 AlN (0001) 上的 N 比通过传统 X 射线衍射方法确定的晶格弛豫的临界层厚度薄约两个数量级。为了避免 QW 光学特性的退化，Al _y Ga _{1− y} N ( y > x ) 底层是有效的。