III-V Semiconductor Nanowires: Attaining Control over Doping and Heterointerfaces

III-V 族半导体纳米线：实现对掺杂和异质界面的控制

• 批准号: EP/M017095/1
• 负责人: Michael Johnston
• 金额: $ 80.34万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FM017095%2F1
• 关键词: III; Semiconductor; Nanowires; Attaining; Control

Semiconductor nanowires (NWs) of group III-V materials have emerged over the past decade as promising ingredients for nanoscale devices and interconnects. NWs offer great opportunities for nanoscale optoelectonic devices, including field-effect transistors, lasers, photodetectors and single-electron memory devices. In addition, NWs are ideal ingredients for next-generation solar cells as they are typically single crystal hexagonal rods of around 5nm in diameter and a few microns length, thus offering excellent conduction pathways to photo-generated charges. III-V semiconductors currently hold the efficiency records of light to electrical power conversion efficiency for conventional planar solar cells, yet they are generally only used in specialised applications such space missions and in solar concentrator arrays owing to their high production cost. The ability to make cheaper, and more efficient solar panels will change the economics in favour of photovoltaics and see a much larger proportion of electricity generation from solar cells. Nanowires are relatively cheap to produce as their growth substrates need not be single crystals and can be recycled. Furthermore the nanoscale geometry of nanowires can be easily manipulated to minimise reflective loss of incident sunlight. However, while early results on NW photovoltaics have been highly promising, these also highlighted that the application of NWs in solar cells crucially relies on electrically doping them accurately and reproducibly. Thus the inability to reliably dope nanowires has become the major obstacle to developing and exploiting any new nanowire based devices. Attaining such control is crucial as it allows directional charge flow along intended device routes. In this research programme we will attack this major obstacle using two a two-fold approach. (1) We will exploit novel techniques of modulation doping in core-shell nanowires to achieve reliable nanowire doping and surface trap passivation; and (2) We will explore alternatives to doping by developing methods to channel charge flow based on interfacial charge transfer at built-in semiconductor heterojunctions. We will tackle these aims with a broad team of experts on both nanowire growth technology and advanced spectroscopic analysis. Relatively few techniques are suitable for assessing the carrier concentration in nanowires, owing to their geometry. We will explore nanowires developed through a range of routes, using a powerful combination of spectroscopic methods based on Optical Pump Terahertz Probe spectroscopy and time- and spatially-resolved photoluminescence spectroscopy. This spectroscopic methodology benefit from being a non-contact method, i.e. the physical observables derived from the measurement are not obscured by variations in the contacts, but reflect the intrinsic properties of the nanowire ensemble. Through these cutting-edge analytical techniques we will advance both of the current leading approches to bottom-up growth of single crystal semiconductor nanowires, which are molecular beam epitaxy (MBE) and metal organic chemical vapour deposition (MOCVD). Having leading research groups on both MBE (Australian National University) and MOCVD (Ecole Polytechnique Federale de Lausanne) growth as partners on this project will allow for the first time a direct comparison of their different approaches to nanowire doping. Through this joint-up approach, we will establish general nanowire design parameters that give a crucial boost to the growth and implementation of semiconductor nanowires in nanoscale optoelectronics devices and next-generation solar cells.

III-V 族材料的半导体纳米线 (NW) 在过去十年中出现，成为纳米级器件和互连的有前途的成分。纳米线为纳米级光电器件提供了巨大的机会，包括场效应晶体管、激光器、光电探测器和单电子存储器件。此外，纳米线是下一代太阳能电池的理想成分，因为它们通常是直径约为 5 纳米、长度为几微米的单晶六角棒，从而为光生电荷提供了良好的传导路径。 III-V族半导体目前保持着传统平面太阳能电池光能转换效率的记录，但由于其生产成本较高，通常仅用于太空任务和太阳能聚光阵列等特殊应用。制造更便宜、更高效的太阳能电池板的能力将改变经济，有利于光伏发电，并看到太阳能电池发电的比例更大。纳米线的生产相对便宜，因为它们的生长基底不需要是单晶并且可以回收利用。此外，可以轻松操纵纳米线的纳米级几何形状，以最大限度地减少入射阳光的反射损失。然而，虽然纳米线光伏发电的早期结果非常有希望，但这也凸显出纳米线在太阳能电池中的应用关键依赖于准确且可重复的电掺杂。因此，无法可靠地掺杂纳米线已成为开发和利用任何新的基于纳米线的设备的主要障碍。实现这种控制至关重要，因为它允许电荷沿着预期的器件路径定向流动。在本研究计划中，我们将使用两种双重方法来解决这个主要障碍。 （1）开发核壳纳米线调制掺杂新技术，实现可靠的纳米线掺杂和表面陷阱钝化； (2) 我们将通过开发基于内置半导体异质结界面电荷转移的电荷流通道方法来探索掺杂的替代方案。我们将与纳米线生长技术和先进光谱分析方面的广泛专家团队一起实现这些目标。由于纳米线的几何形状，适合评估纳米线载流子浓度的技术相对较少。我们将使用基于光泵太赫兹探针光谱和时间和空间分辨光致发光光谱的光谱方法的强大组合，探索通过一系列途径开发的纳米线。这种光谱方法得益于非接触方法，即从测量中得出的物理可观测值不会因接触的变化而模糊，而是反映了纳米线系综的固有特性。通过这些尖端的分析技术，我们将推进目前单晶半导体纳米线自下而上生长的两种领先方法，即分子束外延（MBE）和金属有机化学气相沉积（MOCVD）。拥有MBE（澳大利亚国立大学）和MOCVD（洛桑联邦理工学院）生长方面领先的研究小组作为该项目的合作伙伴，将首次直接比较他们不同的纳米线掺杂方法。通过这种联合方法，我们将建立通用纳米线设计参数，为纳米级光电子器件和下一代太阳能电池中半导体纳米线的生长和应用提供至关重要的推动。

项目成果

In(x)Ga(1-x)As nanowires with uniform composition, pure wurtzite crystal phase and taper-free morphology.

In(x)Ga(1-x)As纳米线成分均匀，纤锌矿晶相纯，形貌无锥度。

• DOI: http://dx.10.1088/0957-4484/26/20/205604
• 发表时间: 2015
• 期刊: Nanotechnology
• 影响因子: 3.5
• 作者: Ameruddin AS

Bimolecular recombination in methylammonium lead triiodide perovskite is an inverse absorption process.

甲基铵三碘化铅钙钛矿中的双分子重组是一个逆吸收过程。

• DOI: http://dx.10.1038/s41467-017-02670-2
• 发表时间: 2018
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Davies CL

Low ensemble disorder in quantum well tube nanowires.

量子阱管纳米线中的低系综无序。

• DOI: http://dx.10.1039/c5nr06996c
• 发表时间: 2015
• 期刊: Nanoscale
• 影响因子: 6.7
• 作者: Davies CL

Investigations of doping via optical pump terahertz-probe spectroscopy

通过光泵太赫兹探针光谱研究掺杂

• DOI: 10.1109/irmmw-thz.2017.8066895
• 发表时间: 2017-08-01
• 期刊: 2017 42nd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)
• 作者: J. Bol;A. Casadei;G. Tütüncouglu;F. Matteini;C. Davies;F. Gaveen;F. Amaduzzi;H. Joyce;L. Herz;A. Fontcuberta i Morral;M. Johnston
• 通讯作者: M. Johnston

Towards higher electron mobility in modulation doped GaAs/AlGaAs core shell nanowires.

调制掺杂 GaAs/AlGaAs 核壳纳米线中实现更高的电子迁移率。

• DOI: http://dx.10.1039/c7nr00680b
• 发表时间: 2017
• 期刊: Nanoscale
• 影响因子: 6.7
• 作者: Boland JL