EAGER: Collaborative Research: Epitaxial Stabilization of Polar Epsilon-phase Gallium Oxide Thin Films

EAGER：合作研究：极性 Epsilon 相氧化镓薄膜的外延稳定性

• 批准号: 1931652
• 负责人: Sriram Krishnamoorthy
• 金额: $ 8.5万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1931652&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Research; Epitaxial; Stabilization

Non-technical description: Semiconductors and ferroelectrics are ubiquitous electronic materials. In semiconductors, the conductivity can be tuned using doping and the velocity of charge carriers in typical semiconductors used for device applications is large. Ferroelectric materials exhibit inherent electric polarization that can be reversed using an external electric field; however charge carriers in ferroelectrics typically have lower electron velocity. This research aims at combining both the properties in a single material by stabilizing a new ferroelectric semiconductor based on the metastable, epsilon phase of gallium oxide. This project is an early effort on developing a fundamental understanding of how the structure and synthesis conditions of epsilon-phase gallium oxide affects its material properties. Theoretical studies and predictions guide the experimental efforts. By combining the properties of semiconductors and ferroelectrics in epsilon-phase gallium oxide, this project aims to unlock its potential, prospects and limitation for devices with multiple functionalities, such as power, high frequency, and memory, all in a single materials platform. The project provides training to undergraduate and graduate students and a post-doctoral scholar to synergistically combine theory and modeling, advanced material synthesis, and materials characterization to develop fundamental structure-property correlations in this new class of materials. Technical description: The metastable, epsilon phase of gallium oxide has been predicted to be a rare, ferroelectric semiconductor with an ultra-wide band gap. This project seeks to stabilize epsilon-phase gallium oxide using epitaxy and demonstrate electric-field switching of polar domains. The research employs a combination of first-principles density-functional theory calculations and metal-organic vapor phase epitaxy to grow epsilon gallium oxide thin films on various predicted substrates and control their quality. It uses a variety of characterization techniques, including aberration-corrected scanning transmission electron microscopy, to characterize the structure, electrical, optical and polar properties of the deposited thin-films and develop structure-property-processing correlations. The realization of high-quality ferroelectric semiconductor based on epsilon-phase gallium oxide is expected to open up pathways to design novel devices for power and high-frequency electronics, information storage and processing applications. Education and outreach aspects include training of undergraduate and graduate students and the organization of a summer program for high-school students and teachers from Utah-region schools to the Utah Nanofab and epitaxy facility to provide exposure to nanotechnology.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.

非技术描述：半导体和铁电体是普遍存在的电子材料。在半导体中，电导率可以使用掺杂来调节，并且用于器件应用的典型半导体中的电荷载流子的速度很大。铁电材料表现出可以使用外部电场反转的固有电极化;然而，铁电体中的电荷载流子通常具有较低的电子速度。这项研究的目的是通过稳定一种新的铁电半导体的基础上的亚稳态，氧化镓的双相结合在一个单一的材料的属性。该项目是对ε相氧化镓的结构和合成条件如何影响其材料性能的基本理解的早期努力。理论研究和预测指导实验工作。通过结合ε相氧化镓中半导体和铁电体的特性，该项目旨在释放其潜力，前景和限制，用于具有多种功能的设备，如电源，高频和存储器，所有这些都在单一材料平台上。该项目为本科生和研究生以及博士后学者提供培训，以协同联合收割机理论和建模，先进的材料合成和材料表征，以开发这类新材料的基本结构-性能相关性。技术说明：氧化镓的亚稳相被预测为具有超宽带隙的稀有铁电半导体。本计画旨在利用磊晶技术稳定ε相氧化镓，并展示极性域的电场切换。该研究采用第一性原理密度泛函理论计算和金属有机气相外延相结合，在各种预测的衬底上生长氧化镓薄膜，并控制其质量。它使用各种表征技术，包括像差校正扫描透射电子显微镜，表征沉积薄膜的结构，电学，光学和极性特性，并开发结构-特性-加工相关性。基于ε相氧化镓的高质量铁电半导体的实现有望为设计用于功率和高频电子学、信息存储和处理应用的新型器件开辟道路。教育和外展方面包括本科生和研究生的培训，以及为来自犹他州地区学校的高中学生和教师组织一个暑期项目，到犹他州纳米工厂和外延设施提供接触纳米技术的机会。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

项目成果

In Situ Dielectric Al 2 O 3 /β‐Ga 2 O 3 Interfaces Grown Using Metal–Organic Chemical Vapor Deposition

使用金属有机化学气相沉积生长的原位电介质 Al 2 O 3 /β-Ga 2 O 3 界面

• DOI: 10.1002/aelm.202100333
• 发表时间: 2021
• 期刊: Advanced Electronic Materials
• 影响因子: 6.2
• 作者: Roy, Saurav;Chmielewski, Adrian E.;Bhattacharyya, Arkka;Ranga, Praneeth;Sun, Rujun;Scarpulla, Michael A.;Alem, Nasim;Krishnamoorthy, Sriram
• 通讯作者: Krishnamoorthy, Sriram