Ballistic Electron Emission Luminescence and Microscopy for Complementary Optical and Electronic Characterization of Buried III-V Semiconductor Heterostructures on the Local Scale

弹道电子发射发光和显微镜在局部尺度上对掩埋 III-V 族半导体异质结构进行互补光学和电子表征

• 批准号: 9906047
• 负责人: Venkatesh Narayanamurti
• 金额: $ 24万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9906047&HistoricalAwards=false
• 关键词: Ballistic; Electron; Emission; Luminescence; Microscopy

9906047NarayanamurtiTo improve the performance of quantum devices, there is an increasing demand for nanometer-scale characterization of semiconductor structures. Under prior NSF support, The PI's have pioneered the use of the Ballistic electron emission microscopy (BEEM) as a powerful new low energy electron microscopy for lateral imaging and spectroscopy (also with nm resolution) for buried structures placed up to 10 nm below the surface.They now propose a novel variant of BEEM by adding the capability of simultaneous BEEM-induced luminescence (BEEL) to probe novel optoelectronic quantum heterostructures based on arsenides, nitrides, phosphides, and antimonides.A combination of BEEM and photons offers distinct advantages. First, by detecting photons emitted from a BEEM, sensitive optical techniques may be used for detection and analysis. Photons thus represent a particularly rich, additional channel of information to study semiconductor heterostructures. Second, by exciting the photon emission with BEEM, a well-defined source is used. Its lateral extension is of atomic dimensions (~ few nm) and its distance from the sample, a crucial factor in any near-field technique, may be controlled with picometer precision. Third, a comparative analysis of BEEM and BEEL would allow simultaneous spatial mapping of both optical and electronic properties of buried semiconductor structures with high spatial resolution and to study their correlation.The optical and transport properties of the buried semiconductor structures will be studied by using the integrated BEEM/BEEL system, wherein we will use a tunneling-electron beam from the tip of BEEM as a local excitation source of BEEL. In this way, in addition to BEEM current, they will record BEEL spectra as well as maps of BEEL as a function of lateral position of the tip. To collect effectively the luminescence signal while conserving a good thermal and electrical isolation of the tip-to-sample zone, they propose to use high numerical-aperture fibers spaced close to the sample. In addition, the use of a metal-coated optical fiber as a STM tip will allow us to take an advantage of the combined NSOM and BEEM measurements. Optional photoexcitation of the structure will also allow them to study spatially-resolved photoluminescence (PL) and PL excitation as well as the BEEM current photomodulation.Such studies using BEEM/BBEEL have never been done before. Through such studies, they expect to advance their understanding of carrier transport and recombination dynamics in technologically important quantum structures such as AlGaN/GaN and GaInP/GaAs quantum wells as well as InP and GaSb self-assembled quantum dots, of the effect of ordering in spontaneously ordered GaInP2, alloys, and of the nano-scaled defects and dislocations in GaN.***

9906047Narayanamurti 为了提高量子器件的性能，对半导体结构的纳米级表征的需求不断增加。 在 NSF 之前的支持下，PI 率先使用弹道电子发射显微镜 (BEEM) 作为一种强大的新型低能电子显微镜，用于表面以下 10 nm 的掩埋结构的横向成像和光谱学（也具有 nm 分辨率）。他们现在提出了一种 BEEM 的新变体，通过添加同时 BEEM 诱导发光 (BEEL) 的能力来探测新的 基于砷化物、氮化物、磷化物和锑化物的光电量子异质结构。BEEM 和光子的结合具有独特的优势。 首先，通过检测从 BEEM 发射的光子，可以使用灵敏的光学技术进行检测和分析。 因此，光子代表了研究半导体异质结构的特别丰富的附加信息通道。 其次，通过使用 BEEM 激发光子发射，使用了明确的光源。 它的横向延伸具有原子尺寸（〜几纳米），并且它与样品的距离是任何近场技术的关键因素，可以用皮米精度进行控制。 第三，BEEM和BEEL的比较分析将允许以高空间分辨率同时空间映射掩埋半导体结构的光学和电子特性，并研究它们的相关性。掩埋半导体结构的光学和传输特性将通过使用集成BEEM/BEEL系统来研究，其中我们将使用来自BEEM尖端的隧道电子束作为局部激发源 比尔。 这样，除了 BEEM 电流之外，他们还将记录 BEEL 光谱以及作为尖端横向位置函数的 BEEL 图。 为了有效地收集发光信号，同时保持尖端与样品区域的良好热隔离和电隔离，他们建议使用靠近样品的高数值孔径光纤。 此外，使用金属涂层光纤作为 STM 尖端将使我们能够利用 NSOM 和 BEEM 组合测量的优势。 该结构的可选光激发还将使他们能够研究空间分辨光致发光 (PL) 和 PL 激发以及 BEEM 电流光调制。以前从未进行过使用 BEEM/BBEEL 的此类研究。 通过这些研究，他们希望加深对技术上重要的量子结构（如 AlGaN/GaN 和 GaInP/GaAs 量子阱以及 InP 和 GaSb 自组装量子点）中的载流子传输和复合动力学、自发有序 GaInP2、合金中的有序效应以及 GaN 中纳米级缺陷和位错的理解。***