ZnO/GaN Heterostructure-based Novel Acousto-electronic Devices

本研究的目的是研究氧化锌/氮化镓异质结中的声电相互作用，并研制由压电层和极性半导体氧化锌/氮化镓异质结组成的可调谐器件。这些方法包括：(I)利用MOCVD在c面蓝宝石衬底上生长极性的ZnO/GaN异质结，并在异质外延过程中通过界面工程控制其极性；(Ii)将压电性的ZnO薄膜与半导体ZnO/GaN异质结集成，形成新型的ZnO/GaN声电子器件，研究和模拟其特性，包括色散和多模表面声波特性、导带偏移和片电子浓度。智能优点：新型的ZnO/GaN声电子器件具有声速高、宽频带机电耦合系数大、采用高阶波模式的工作频率高、低偏置电压下可调谐大、功能齐全、制造成本低等优点。更广泛的影响：多功能氧化锌与半导体GaN的集成将推动材料集成和器件技术达到一个新的水平；因此，开辟了新的研究机会和应用。研究和教育的融合是这个项目的一个重要重点。学生将获得材料生长、界面物理、综合表征、器件设计和模拟以及制造工艺方面的跨学科知识基础。这项研究将通过与行业合作伙伴的大力合作来促进。通过州长学校、罗格斯科学巴士计划和特别暑期计划，教育外展努力针对新泽西州的高中生。

The objective of this research is to study the acousto-electrical interaction in ZnO/GaN heterostructures and develop the tunable devices which comprise of a piezoelectric ZnO layer and a polar semiconductor ZnO/GaN heterostructure. The approaches include: (i) grow the polar ZnO/GaN heterostructure on c-plane sapphire using MOCVD and control its polarity through interface engineering during the heteroepitaxy; and (ii) integrate a piezoelectric ZnO film with the semiconductor ZnO/GaN heterostructure to form novel ZnO/GaN acousto-electronic devices, study and simulate its characteristics, including dispersion and multi-mode surface acoustic wave properties, conduction band offset and sheet electron concentration by considering both spontaneous and piezoelectric polarizations at the ZnO/GaN interface. Intellectual merit: The novel ZnO/GaN acousto-electronic device possesses advantages including high acoustic velocity and large electro-mechanical coupling coefficient over a broad frequency range, high operation frequency using higher order wave modes, large tunability at low biasing voltage, the ability to perform versatile functions, and low manufacturing cost. Broader impact: Integration of multifunctional ZnO with semiconductor GaN will promote a new level of material integration and devices technologies; therefore, open up new research opportunities and applications. The integration of research and education is an important focus of this project. The students will gain interdisciplinary knowledge base in material growth, interface physics, comprehensive characterizations, device design and simulation, and fabrication process. The research will be facilitated by strong collaboration with industrial partners. The educational outreach efforts are directed at NJ high school students, through the Governor's School, Rutgers Science Bus program, and special summer program.