Nitrogen (N) is a common element added to GaAs for band gap engineering and strain compensation. However, detection of small amounts of N is difficult for electron microscopy as well as for other chemical analysis techniques. In this work, N in GaAs is examined by using different transmission electron microscopy (TEM) techniques. While both dark-field TEM imaging using the composition sensitive (002) reflections and selected area diffraction reveal a significant difference between the doped thin-film and the GaAs substrate, spectroscopy techniques such as electron energy loss and energy dispersive X-ray spectroscopy are not able to detect N. To quantify the N content, quantitative convergent beam electron diffraction (QCBED) is used, which gives a direct evidence of N substitution and As vacancies. The measurements are enabled by the electron energy-filtered scanning CBED technique. These results demonstrate a sensitive method for composition analysis based on quantitative electron diffraction.

氮 (N) 是添加到 GaAs 中的常见元素，用于带隙工程和应变补偿。然而，电子显微镜和其他化学分析技术很难检测到少量的 N。在这项工作中，使用不同的透射电子显微镜 (TEM) 技术检查 GaAs 中的 N。虽然使用成分敏感 (002) 反射和选区衍射的暗场 TEM 成像都揭示了掺杂薄膜和 GaAs 衬底之间的显着差异，但诸如电子能量损失和能量色散 X 射线光谱等光谱技术并不能够检测 N。为了量化 N 含量，使用了定量会聚束电子衍射 (QCBED)，它提供了 N 取代和 As 空位的直接证据。测量是通过电子能量过滤扫描 CBED 技术实现的。这些结果证明了基于定量电子衍射的成分分析的灵敏方法。