Charge Carrier Transport Analysis in Radial and Axial Charge-Separating Junctions of III/V Semiconductor Nanowires

III/V 半导体纳米线径向和轴向电荷分离结中的载流子传输分析

• 批准号: 428769263
• 负责人: Professor Dr. Thomas Hannappel
• 金额: --
• 依托单位: Lehrstuhl für Bauelemente der Höchstfrequenzelektronik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/428769263?language=en
• 关键词: Charge; Carrier; Transport; Analysis; Radial

A wide variety of nanowire devices are nowadays available at the level of laboratory samples. In particular, those consisting of compound semiconductor materials have extended the spectrum of electronic and photonic capabilities by implementing homo- and heterostructures in nanowire topologies. However, the overall performance remains far below expectations und hampers decisively a commercial implementation. This applies, for example, to the capability to convert light to electrical energy or to produce electrically pumped light emitters or even LASERs. Up to now, nanowire research has neglected the investigation of inherent limitations of these technologies. However, in order to open up new markets for nanowire devices or to even replace established semiconductor devices based on planar structures in existing markets, substantial qualitative rather than only quantitative improvements are required. This project deals with the inherent limitations in the interaction between light and nanowire such as light-current conversion in radial as well as axial nanowire structures.The project aims to identify the origin of the limitations in optoelectronic performance within the device structure, including microscopic analysis. The work program entails an intense correlation between macroscopic device data and spatially highly-resolved microscopy data. The devices incorporate axial and radial nanowire heterojunctions for charge separation, consisting of GaAs- and InGaP-based pn-homo- and heterojunctions, which are fabricated by MOVPE. The interrelation between interface formation and recombination paths is to be investigated by a combination of in-system 4-tip measurements, scanning probe microscopy and optical methods. In particular, we record local current-voltage characteristics applied to axial versus radial nanowire structures combined with high-resolution scanning tunneling microscopy. The investigation of optoelectronic properties is carried out using a streak-camera system. Both, measurement techniques and their localization are inherently limited in nanostructures, hence requiring physical modeling. Here, modeling is performed by the simulation software package Silvaco Atlas. The performance data feeding into conversion efficiencies are obtained taking generation and recombination mechanisms into account as well as minority and tunneling transport across the pn junctions.The aim of the project is the identification of the qualitative and quantitative interrelation between nanowire growth, device design, interface formation, and surface passivation with respect to the quality of different charge-separating pn-junctions in the nanowires. Thereby, concepts for a significant increase of the optoelectronic performance in the light-nanowire interaction will be proposed and demonstrated.

如今，实验室样品水平上有各种各样的纳米线器件。特别是，由化合物半导体材料组成的材料通过在纳米线拓扑中实现同质和异质结构，扩展了电子和光子能力的范围。然而，整体性能仍然远低于预期，并且严重阻碍了商业实施。例如，这适用于将光转换为电能或生产电泵浦光发射器甚至激光的能力。到目前为止，纳米线研究忽略了对这些技术固有局限性的研究。然而，为了开辟纳米线器件的新市场，或者甚至取代现有市场中基于平面结构的现有半导体器件，需要实质性的定性改进，而不仅仅是定量改进。该项目涉及光和纳米线之间相互作用的固有限制，例如径向和轴向纳米线结构中的光电流转换。该项目旨在确定器件结构内光电性能限制的根源，包括微观分析。该工作计划需要宏观设备数据和空间高分辨率显微镜数据之间的密切相关性。该器件结合了用于电荷分离的轴向和径向纳米线异质结，由基于 GaAs 和 InGaP 的 pn 同质结和异质结组成，由 MOVPE 制造。界面形成和复合路径之间的相互关系将通过系统内 4 尖端测量、扫描探针显微镜和光学方法的组合来研究。特别是，我们结合高分辨率扫描隧道显微镜记录了应用于轴向与径向纳米线结构的局部电流-电压特性。光电特性的研究是使用条纹相机系统进行的。测量技术及其定位本质上都受到纳米结构的限制，因此需要物理建模。这里，建模是通过仿真软件包 Silvaco Atlas 进行的。获得转化效率的性能数据时考虑了生成和重组机制以及跨 pn 结的少数和隧道传输。该项目的目的是确定纳米线生长、器件设计、接口之间的定性和定量相互关系形成和表面钝化与纳米线中不同电荷分离 pn 结的质量有关。因此，将提出并论证显着提高光-纳米线相互作用中光电性能的概念。