Emergent Phenomena at Flat Interfaces between Nitrides and Oxides

该项目得到了材料研究部电子和光子材料计划以及陶瓷计划的支持。非技术描述：Maria和Sitar的NCSU(北卡罗来纳州立大学)研究团队探索氮化物和氧化物半导体的连接，并特别关注连接它们的界面。如果准备得当，这些界面可以容纳高度集中的高速电子，这些电子被限制在二维层中。这种新型材料被设计成在界面上具有可控的电子密度，并为未来的电子设备打开了新的可能性。该研究项目涉及本科生研究生。该小组通过各种教育外展活动传播研究成果。例如，一年一度的NCSU科学和数学互动学习体验(SMILE)夏令营邀请中学生和高级五年级学生在PI的研究实验室探索材料科学原理。技术描述：Maria和Sitar研究团队探索复合氧化物(如MgO-CaO)和GaN之间的半导体级异质外延界面。这些异质结构的性质和性能由组成晶体的电子结构来调节，而不是不想要的缺陷、结构缺陷或不想要的化学相互作用。两类材料的无缝集成有望创造出将其特性紧密结合在一起的途径。为了实现这些目标，该团队结合了两种先进的材料合成方法：表面活性剂辅助薄膜生长和受限外延。表面活性剂辅助生长克服了氧化物刻面的挑战，而受限外延产生了无步骤的表面，从而产生了完美的平坦界面。使用这些方法，该团队将在化合物半导体中将高室温载流子迁移率与电子氧化物的非线性性质响应叠加在一起。这种独特的氧化物/氮化物异质结构为电子、磁、光和界面物理提供了一个新的前沿。

This project is supported by the Electronic and Photonic Materials Program and by the Ceramics Program, both in the Division of Materials Research.Nontechnical Description: The NCSU (North Carolina State University) research team of Maria and Sitar explores the junction of nitride and oxide semiconductors with specific attention to the interfaces that bond them. When correctly prepared, these interfaces can host a high concentration of high-speed electrons that are confined to a two-dimensional layer. This new type of material is designed to have controllable electron density at the interface and opens new possibilities for future electronic devices. The research project involves graduate undergraduate students. The team disseminates the research findings through various educational outreach activities. For example, the annual NCSU Science and Mathematics Interactive Learning Experience (SMILE) camp engages middle-school and advanced fifth grade students to explore the principles of materials science in the PIs' research labs.Technical Description: The Maria and Sitar research team explores semiconductor-grade heteroepitaxial interfaces between complex oxides (e.g., MgO-CaO) and GaN. The properties and performance of these heterostructures are regulated by the electronic structure of the constituent crystals as opposed to unwanted defects, structural imperfections, or undesired chemical interactions. Seamless integration across two classes of materials is expected to create pathways to intimately couple their properties. To accomplish these goals, the team combines two advanced materials synthesis methods: surfactant-assisted film growth and confined epitaxy. Surfactant assisted growth overcomes the challenges of oxide faceting, while confined epitaxy creates step-free surfaces and thus perfectly flat interfaces. Using these approaches, the team is positioned to superimpose high room-temperature carrier mobility in compound semiconductors with nonlinear property responses of electronic oxides. This unique oxide/nitride heterostructure provides access to a new frontier of electronic, magnetic, optical, and interface physics.