Nonpolar Si-doped AlGaN with high electron concentration (EC) and superior surface morphology (SM) layers were successfully grown on r-plane sapphire substrates for the first time with metal organic chemical vapor deposition technology. X-ray diffraction, cross-sectional scanning electron microscope, ultraviolet–visible absorption spectroscopy, atomic force microscopy, and Hall measurements were used to examine the influence of indium surfactant and an extra AlGaN buffer on crystalline quality (CQ), SM, and electrical characteristics of the nonpolar Si-doped n-AlGaN, respectively. The characterization results revealed that the anisotropy in CQ of the nonpolar Si-doped n-AlGaN epi-layers was suppressed effectively, and the SM, as well as the electrical properties including EC, electron mobility (EM), and electron resistivity (ER), had been significantly improved by using indium surfactant and an extra AlGaN buffer layer. In fact, an EC as high as 4.8 × 1017 cm−3, an EM up to 3.42 cm2/V s, an ER down to 4.78 Ω∙\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \bullet $$\end{document}cm , and a root-mean-square value as small as 8.2 nm for surface roughness was achieved for the nonpolar Si-doped n-AlGaN with a relatively high Al composition of 50%.

中文翻译：

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非极性 a 面 Si 掺杂 n-AlGaN 结构和电学特性的改进

首次采用金属有机化学气相沉积技术在 r 面蓝宝石衬底上成功生长出具有高电子浓度 (EC) 和优异表面形态 (SM) 层的非极性 Si 掺杂 AlGaN。X 射线衍射、横截面扫描电子显微镜、紫外-可见吸收光谱、原子力显微镜和霍尔测量用于检查铟表面活性剂和额外的 AlGaN 缓冲液对晶体质量 (CQ)、SM 和电学的影响。分别为非极性 Si 掺杂 n-AlGaN 的特性。表征结果表明，非极性Si掺杂的n-AlGaN外延层的CQ各向异性得到有效抑制，SM以及包括EC、电子迁移率（EM）和电子电阻率（ER）在内的电学特性得到有效抑制。 , 通过使用铟表面活性剂和额外的 AlGaN 缓冲层得到显着改善。事实上，EC 高达 4.8 × 1017 cm−3，EM 高达 3.42 cm2/V s，ER 低至 4.78 Ω∙\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Omega \bullet $$\end {document}cm ，并且对于具有 50% 的相对较高的 Al 成分的非极性 Si 掺杂 n-AlGaN 实现了小至 8.2 nm 的表面粗糙度的均方根值。