The influence of doping and annealing onto the lattice dynamics, band structure and free charge carrier properties in monoclinic gallium aluminum oxide semiconductor alloys

非技术描述：该项目为开发用于电子器件的新型半导体材料提供了科学基础，可以实现电网内实时低损耗的电力分配能力。这种分布可以通过能够开关和分配高电压和负载的大功率电子设备来控制。作为一类新型半导体材料，镓铝氧化物是制造此类器件的一个有前途的候选材料。本项目通过采用各种理论和实验表征技术，研究掺杂和成分对材料电子性能的影响。该项目为本科生和研究生提供各种培训机会，以及针对K-12学生、教师、少数民族和弱势群体的各种外展活动。该项目包括内布拉斯加州高中和初中学生的暑期研究项目和课后科学教育活动，每年的公共社会和学术推广项目扩大到包括在内布拉斯加州大学州立博物馆的电力电子和未来电网的演示和周日演讲，面向小学到高中的学生。技术描述：本项目重点研究具有高功率电子应用潜力的新型宽禁带材料的基础材料。研究了掺杂和退火对单斜对称半导体氧化铝镓合金电子性能的影响。主要目的是确定声子、能带结构和自由载流子的有效质量和迁移率参数，包括它们的各向异性，作为：(i)铝成分变化，（ii）锡、锗和硅掺杂浓度，（iii）在不同气体环境下在宽温度范围内退火的函数。该项目结合了计算理论和实验表征。密度泛函理论计算用于预测掺杂（缺陷）和合金化的影响，并指导实验技术-广义光谱椭偏和光学霍尔效应-的应用，以确定单晶和低对称性半导体异质结构中的电子、声子和输运性质。其他技术包括拉曼光谱和原位高温研究。本研究有助于基于新型单斜半导体材料的高功率电子器件的技术发展，并为研究生和青年研究人员在多元文化环境下的先进半导体技术提供教育和研究培训的可能性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Description: This project provides a scientific basis for development of novel semiconductor material for electronic devices that could enable real-time low-loss electric power distribution capability within the electric grid. Such distribution can be controlled by high-power electronic devices capable of switching and distributing high voltages and loads. As a new class of semiconductor materials, gallium aluminum oxide emerges as a promising candidate for fabrication of such devices. This project investigates the influence of doping and composition onto the resulting electronic properties of the material by employing a variety of theoretical and experimental characterization techniques. This project offers various training opportunities for undergraduate and graduate students, along with various outreach activities targeting K-12 students, teachers, minorities and underrepresented groups. The project includes Nebraska high-school and middle-school student summer research programs and after-school science education activities, and annual public Social and academic outreach programs are expanded to include demonstrations and Sunday presentations at the University of Nebraska State Museum on power electronics and the electric grid of the future for elementary to high school students.Technical Description: The project focuses on a fundamental material investigation of novel wide-bandgap material with potential in high power electronic applications. The research investigates the effect of doping and annealing on the electronic properties of semiconductor aluminum gallium oxide alloys with monoclinic symmetry. The main objectives are to determine the phonon, band structure and free charge carrier effective mass and mobility parameters, including their anisotropy, as a function of: (i) aluminum composition variation, (ii) tin, germanium and silicon doping concentrations and (iii) annealing under different gaseous environments in wide temperature ranges. The project combines computational theory and experimental characterization. Density functional theory calculations are performed to predict the effects of doping (defects) and alloying and to guide the applications of the experimental techniques - generalized spectroscopic ellipsometry and the optical Hall effect - to determine the electronic, phonon and transport properties in single crystals and heterostructures of low-symmetry semiconductors. Additional techniques include Raman spectroscopy and in-situ high-temperature studies. This research contributes to the technological development of high power electronic devices based on novel monoclinic semiconductor materials and provides education and research training possibilities for graduate students and young researchers in advanced semiconductor technology in culturally diverse environment.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.