Excellence in Research: GaAsSb/GaAs Nanowires based Avalanche Photodetectors on Si

卓越的研究：基于 Si 上的 GaAsSb/GaAs 纳米线雪崩光电探测器

• 批准号: 1832117
• 负责人: Shanthi Iyer
• 金额: $ 50万
• 依托单位: North Carolina Agricultural & Technical State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1832117&HistoricalAwards=false
• 关键词: Excellence; Research; GaAsSb; GaAs; Nanowires

An important building block of the quantum information circuit is the single photon detection device. The avalanche photodetector in the nanowire configuration is a promising route to achieving single photon detection as it enables reduction in the impact ionization region, thus improving gain and detectivity. Further, the relaxation of the lattice mismatch constraint in the nanowire configuration enables integration of the avalanche photodetector to the traditional silicon technology. GaAsSb is an ideal material system for wavelength tunability in the optical communication wavelength range of 1.3 - 1.55 microns. The GaAsSb/GaAs heterostructure will be designed for independent multiplication and absorption regions, with the former occurring in the larger bandgap GaAs junction to minimize the effect of Zener breakdown, which is a common problem in low band gap materials. This proposal's central theme is on the growth and design optimization of the separate optical absorption and multiplication region in the GaAsSb/GaAs nanowire based avalanche photodetector heterostructure on Si. Two different nanowire configurations namely axial and core-shell will be examined using a variety of material and device characterization techniques. The experimental work will be complemented by modeling using different software packages. Emphasis will be on engineering the increase of the electric field in 3D and gaining deeper insight into the avalanche mechanism (multiplication of the carriers) in the two different nanowire configurations. The performance in these two configurations will be evaluated to arrive at an optimized design in the final phase to achieve nano-avalanche photodetector with gain exceeding 10 in the near infrared region. Technical: Avalanche photodetectors are commonly used for high speed, high gain and low optical signal detection applications. The interest in nanowire - based avalanche photodetectors stems from the potential success of single photon detection devices. Nanowire architecture due to its one dimensional attributes leads to unique and novel material properties and concomitantly enables adaptation of fabrication processes from thin film technology. The relaxation of lattice mismatch constraint, small footprint, high surface to volume ratio, superior optical trapping and feasibility of implementing in different nanowire architectures can be strategically used to improve the detector performance and enabling heterogeneous integration with traditional Si technology. In the proposed work, separate optical absorption and multiplication region avalanche photodetector concepts from the thin film form will be adapted toward bandgap engineering of GaAsSb/GaAs heterostructure in a unique manner, exclusive to the nanowire architecture. The GaAsSb material system has been chosen as it encompasses the bandgap tunable in the telecommunication wavelength region. Different design concepts in the implementation of avalanche photodetector will be realized: axial and radial architectures, the latter of which is exclusive to the nanowire configuration. The investigation of nanowire ensemble based avalanche photodetectors enable taking advantage of the vertical alignment that allows superior light trapping properties leading to enhanced optical absorption. The performance in the two different configurations will be evaluated to arrive at an optimized design in the final phase to achieve nano-avalanche photodetector with gain exceeding 10 in the near infrared region. This study will provide deeper insight into the effect of photoconductivity modulation on the avalanche mechanism in nanowires due to the band bending at the surface stemming from the close proximity of the surface to the core of the NW, particularly in axial architecture. Advances made in the heterostructure design toward achieving an increased 3D electric field in a lower dimensional structure will enable transformational improvement in the device performance with significant impact on material and device research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

量子信息电路的一个重要组成部分是单光子探测装置。纳米线配置中的雪崩光电探测器是实现单光子探测的有前途的途径，因为它能够减少碰撞电离区域，从而提高增益和探测率。此外，纳米线配置中晶格失配约束的放松使得雪崩光电探测器能够集成到传统的硅技术中。 GaAsSb 是在 1.3 - 1.55 微米光通信波长范围内实现波长可调的理想材料系统。 GaAsSb/GaAs异质结构将设计用于独立的倍增和吸收区域，前者出现在较大带隙的GaAs结中，以最大限度地减少齐纳击穿的影响，这是低带隙材料中的常见问题。该提案的中心主题是硅上基于 GaAsSb/GaAs 纳米线的雪崩光电探测器异质结构中单独的光学吸收和倍增区域的生长和设计优化。将使用各种材料和器件表征技术来检查两种不同的纳米线配置，即轴向和核壳。实验工作将通过使用不同软件包进行建模来补充。重点将是设计 3D 电场的增加，并更深入地了解两种不同纳米线配置中的雪崩机制（载流子倍增）。将评估这两种配置的性能，以在最后阶段实现优化设计，以实现近红外区域增益超过10的纳米雪崩光电探测器。技术：雪崩光电探测器通常用于高速、高增益和低光信号检测应用。 对基于纳米线的雪崩光电探测器的兴趣源于单光子探测装置的潜在成功。纳米线结构由于其一维属性而具有独特且新颖的材料特性，并同时能够适应薄膜技术的制造工艺。晶格失配约束的放松、小占地面积、高表面体积比、卓越的光学捕获以及在不同纳米线架构中实现的可行性可以战略性地用于提高探测器性能并实现与传统硅技术的异构集成。在拟议的工作中，薄膜形式的分离光学吸收和倍增区域雪崩光电探测器概念将以纳米线结构独有的独特方式应用于GaAsSb/GaAs异质结构的带隙工程。选择 GaAsSb 材料系统是因为它包含在电信波长区域内可调谐的带隙。雪崩光电探测器的实现将实现不同的设计理念：轴向和径向架构，后者是纳米线配置所独有的。 基于纳米线集合的雪崩光电探测器的研究能够利用垂直对准，从而实现卓越的光捕获特性，从而增强光学吸收。将评估两种不同配置的性能，以在最后阶段得出优化设计，以实现近红外区域增益超过10的纳米雪崩光电探测器。这项研究将更深入地了解光电导调制对纳米线雪崩机制的影响，因为表面与纳米线核心的距离很近，导致表面能带弯曲，特别是在轴向结构中。在异质结构设计方面取得的进步，旨在在低维结构中实现增强的 3D 电场，将实现器件性能的变革性改进，对材料和器件研究产生重大影响。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持利用基金会的智力优势和更广泛的影响审查标准。

项目成果

Space charge limited conduction mechanism in GaAsSb nanowires and the effect of in situ annealing in ultra-high vacuum

GaAsSb纳米线空间电荷有限传导机制及超高真空原位退火效应

• DOI: 10.1088/1361-6528/ab47aa
• 发表时间: 2020-01
• 期刊: Nanotechnology
• 影响因子: 3.5
• 作者: Parakh, Mehul;Johnson, Sean;Pokharel, Rabin;Ramaswamy, Priyanka;Nalamati, Surya;Li, Jia;Iyer, Shanthi
• 通讯作者: Iyer, Shanthi

A Study on the Effects of Gallium Droplet Consumption and Post Growth Annealing on Te- Doped GaAs Nanowire Proper-ties grown by Self-Catalyzed Molecular Beam Epitaxy

镓滴消耗和生长后退火对自催化分子束外延生长的Te掺杂GaAs纳米线性能影响的研究

• DOI: 10.3390/catal12050451
• 发表时间: 2022-04
• 期刊: Catalysts
• 影响因子: 3.9
• 作者: Shisir Devkota1; Mehul Parakh1
• 通讯作者: Mehul Parakh1

A Study of Dopant Incorporation in Te - doped GaAsSb Nanowires using a Combination of XPS/UPS, and C-AFM/SKPM

结合XPS/UPS和C-AFM/SKPM研究Te掺杂GaAsSb纳米线中的掺杂剂掺入

• DOI: 10.1038/s41598-021-87825-4
• 发表时间: 2021-04-15
• 期刊: Scientific report
• 作者: Ramaswamy P;Devkota S;Pokharel R;Nalamati S;Stevie F;Jones K;Reynolds L;Iyer S
• 通讯作者: Iyer S

A study of n-doping in self-catalyzed GaAsSb nanowires using GaTe dopant source and ensemble nanowire near-infrared photodetector

使用 GaTe 掺杂源和集合纳米线近红外光电探测器研究自催化 GaAsSb 纳米线的 n 掺杂

• DOI: 10.1088/1361-6528/abb506
• 发表时间: 2020-10-06
• 期刊: Nanotechnology
• 影响因子: 3.5
• 作者: S. Devkota;M. Parakh;Sean Johnson;Priyanka Ramaswamy;Michael Lowe;A. Penn;Lewis Reynolds;S. Iyer
• 通讯作者: S. Iyer

Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization

通过关联超快太赫兹光谱和光电表征，揭示 Te 掺杂 GaAsSb 和 GaAsSbN 纳米线中的载流子动力学和传输

• DOI: 10.1088/1361-6528/ac7d61
• 发表时间: 2022-03-16
• 期刊: Nanotechnology
• 影响因子: 3.5
• 作者: Long Yuan;R. Pokharel;S. Devkota;Hir;eep Kuchoor;eep;K. Dawkins;Min;Yue;D. Yarotski;S. Iyer;R. Prasankumar
• 通讯作者: R. Prasankumar