Controlling Conductivity in the UV-Transparent Conducting Oxide Ga2O3

控制紫外透明导电氧化物 Ga2O3 的电导率

• 批准号: 1104628
• 负责人: Marjorie Olmstead
• 金额: $ 64万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1104628&HistoricalAwards=false
• 关键词: Controlling; Conductivity; UV; Transparent; Conducting

Technical: This Focused Research Group project, funded jointly by the Electronic and Photonic Materials (EPM) and Ceramics (CER) Programs, encompasses a systematic interdisciplinary effort combining physics, materials science and electrical engineering to elucidate interconnections among the structural, electronic and optical properties of the transparent conductor gallium oxide, Ga2O3, with emphasis on intrinsic and extrinsic defects, interface chemistry, and dimensionality. Ga2O3 is transparent throughout the solar spectrum and into the near ultraviolet (UV), with a band gap of 4.9 eV (wavelength ~ 250 nm), but can be made conductive through doping (e.g., Si or Sn), by processing to create intrinsic defects (e.g. oxygen vacancies or interstitials), or through deep-UV photoabsorption. The anisotropic crystal structure of beta- Ga2O3 contains intrinsic, one-dimensional, open channels, and can be fabricated in structures with arbitrary dimensionality - 3D bulk crystals, 2D films, quasi-1D nanobelts, 1D nanowires and 0D nanospheres - as well as maintain that structure when alloyed with Al2O3 over a wide concentration range. Ga2O3 can undergo resistive switching (RS) with appropriate processing, but unlike more commonly considered transition metal oxides, gallium remains Ga3+ during creation of oxygen vacancies and/or interstitials, placing it in a different class of RS materials. This project will address key issues related to Ga2O3 that are not currently well understood: the interplay between ionic and electronic conductivity in Ga2O3, the nanoscale processes by which surface and interface reactions induce conductivity changes, and the role of the intrinsic channel structure in governing these properties. Ga2O3 has been proposed for several applications, including a "solar-blind" transparent conductor, a resistive switching memory element, an UV only photodetector, a chemical sensor, and a catalysis substrate. This research will contribute to mechanistic understanding of the conductivity and interface reduction-oxidation reactions that govern the operation of these prototype device structures, enabling refinement and enhancement of their function.Non-Technical: This project addresses workforce development at several levels. Graduate students will be actively involved in multidisciplinary research that spans science and engineering, and involves collaboration among academic, industrial and government laboratories in the US and Japan. They will develop key skills across several arenas that will enhance their career opportunities: materials synthesis, table-top sample characterization, synchrotron and other user-facility-based measurements, theoretical modeling, and proposal writing (for user facility access), as well as analytical and both oral and written communication skills as they process, interpret and present their research findings. The project also includes well-defined activities to increase interactions with populations that are frequently unaware of research activities at the University of Washington. Established connections with a local high school at which the majority of students don't typically aim for college will be expanded through active mentoring of high school students to perform photocurrent measurements of oxide samples grown under this proposal, summer research collaboration with the high school teacher who directs the science and robotics clubs there, as well as visits to classrooms to discuss both our science and students career and educational options.

技术支持：这个重点研究小组项目，由电子和光子材料（MEMS）和陶瓷（CER）计划联合资助，包括一个系统的跨学科的努力，结合物理学，材料科学和电气工程，以阐明透明导体氧化镓，Ga 2 O 3的结构，电子和光学特性之间的相互联系，重点是内在和外在缺陷，界面化学，和维度。Ga 2 O3在整个太阳光谱中是透明的，并且进入近紫外（UV），具有4.9eV的带隙（波长约250 nm），但是可以通过掺杂（例如，Si或Sn），通过加工以产生本征缺陷（例如氧空位或杂质），或通过深紫外光吸收。β-Ga 2 O3的各向异性晶体结构包含本征的一维开放通道，并且可以制造成具有任意维度的结构- 3D块状晶体、2D膜、准1D纳米带、1D纳米线和0 D纳米球-并且当与Al 2 O3在宽浓度范围内合金化时保持该结构。Ga 2 O3可以通过适当的处理进行电阻转换（RS），但与更常见的过渡金属氧化物不同，镓在氧空位和/或金属的产生期间保持Ga 3+，将其置于不同类别的RS材料中。该项目将解决与Ga 2 O3相关的关键问题，这些问题目前尚未得到很好的理解：Ga 2 O3中离子和电子电导率之间的相互作用，表面和界面反应引起电导率变化的纳米级过程，以及内在通道结构在管理这些特性中的作用。Ga 2 O3已被提出用于几种应用，包括“日盲”透明导体、电阻开关存储元件、仅UV光检测器、化学传感器和催化衬底。这项研究将有助于对这些原型器件结构的导电性和界面还原-氧化反应的机械理解，从而改善和增强其功能。非技术性：该项目涉及几个层面的劳动力发展。研究生将积极参与跨越科学和工程的多学科研究，并涉及美国和日本的学术，工业和政府实验室之间的合作。他们将在几个领域发展关键技能，这将提高他们的职业机会：材料合成，桌面样品表征，同步加速器和其他基于用户设施的测量，理论建模和提案写作（用于用户设施访问），以及分析和口头和书面沟通技能，因为他们的过程，解释和展示他们的研究结果。该项目还包括明确的活动，以增加与经常不知道华盛顿大学研究活动的人群的互动。与当地一所高中建立的联系，其中大多数学生通常不以大学为目标，将通过积极指导高中学生对根据本提案生长的氧化物样品进行光电流测量，与指导那里的科学和机器人俱乐部的高中教师进行夏季研究合作，以及参观教室，讨论我们的科学和学生的职业和教育选择。