A stack of five Al(Ga)N-based quantum wells is investigated by combined laterally and depth resolved cathodoluminescence (CL) spectroscopy in order to distinguish lateral and vertical inhomogeneities of these wells. Transmission electron microscopy (TEM) micrographs provide data for the real sample structure, which enters into the Monte-Carlo simulation of the depth-resolved CL measurements to refine the depth resolution. The comparison of these CL measurements to the results of electron energy loss spectra (EELS) allows to identify local thickness variations of the lower three quantum wells to be the origin of two different luminescence contributions to the overall spectrum. The differentiation of the two groups of quantum wells by depth-resolved CL is demonstrated.

通过组合横向和深度分辨阴极发光（CL）光谱研究了五个基于Al（Ga）N的量子阱的堆栈，以区分这些阱的横向和垂直不均匀性。透射电子显微镜（TEM）显微照片提供了真实样品结构的数据，该数据进入了深度解析CL测量的蒙特卡洛模拟，以改善深度分辨率。将这些CL测量值与电子能量损失谱（EELS）的结果进行比较，可以确定较低的三个量子阱的局部厚度变化，这是整个光谱的两种不同发光贡献的起源。证明了深度分辨CL对两组量子阱的区分。