硅基氧化锌薄膜生长中的复合缓冲层设计与同价离子替位辅助p型掺杂机理研究

The integration of ZnO-based multi-functional devices on Si substrates is attracting worldwide attention for potential applications in optoelectronic devices. This project will aim at the key issues of high quality ZnO epitaxy on Si substrate and stable p-type ZnO film with high p-type conductivity. In order to improve single-crystalline ZnO films on Si, design of composite buffer layers including X2O3 and low-temperature grown ZnO will be studied. X2O3 buffer layer effectively alleviates the large lattice mismatch between ZnO and Si; low-temperature grown ZnO effectively controls the stress of the epitaxial layer. Meanwhile, the study on heterogeneous nucleation and crystal growth kinetics will be carried out to control the defect density of the epitaxial layer. Accordingly, homovalent substitution assistant p-type doping technique will be explored to develop a stable p-type ZnO film with high p-type conductivity. Research on p-type doping will be focused on the Na-doping mechanism and the influences and mechanisms of Mg substitution on the energy band structure of ZnO, Na acceptor level, neighbor coordination and local strain. It is believed that the studies of this project will see significant progress in the near future and contribute to the integration of ZnO-based ultraviolet optoelectronic devices with Si electronics.

本项目针对Si衬底上制备ZnO发光器件面临的主要挑战，开展Si基ZnO单晶薄膜生长与稳定高效p型掺杂两大关键问题研究。为提高ZnO单晶薄膜质量，提出复合缓冲层的设计方法，通过结合X2O3缓冲层（X=Lu, Sc, Gd）和低温ZnO插入层，有效缓解Si与ZnO的晶格失配。采用分子束外延方法，深入分析异质外延的非均匀成核与晶体生长动力学规律，探索X2O3缓冲层和低温ZnO插入层对薄膜质量的影响机制，并根据其内在耦合关系联合优化，降低ZnO单晶薄膜的缺陷密度、减少应变、解决微裂问题。在此基础上，引入适量Mg进行离子替位调控ZnO薄膜的Na掺杂研究，深入探索同价离子替位辅助p型掺杂机理。揭示Mg替位对Na受主能级、近邻配位和局部应变的调控规律，掌握提高p型ZnO空穴浓度和稳定性的方法与技术。研究成果将为Si衬底上制备发光器件提供系统性的理论参考和创新的技术路线，推动光电子和微电子的集成。

短波长光电子与Si微电子的集成因其重大的应用价值被广泛关注。Si基ZnO材料与光电子器件研究是目前国际上的一个重要课题，然而Si基高质量ZnO单晶材料的制备具有很大的挑战性。本项目主要开展Si基ZnO异质结构的材料生长与p型掺杂研究。在Si（111）衬底上引入Lu2O3（111）缓冲层，有效缓解了Si（111）衬底与ZnMgO薄膜之间的晶格失配，成功实现了ZnMgO薄膜的外延生长。发明了一种新工艺，成功解决了Si（111）衬底上外延生长ZnMgO薄膜的开裂问题，获得了较厚且无微裂纹的ZnMgO外延薄膜。在此基础上，引入Lu2O3（111）缓冲层、ZnO低温形核层和ZnO缓冲层制备出了性能优良的ZnO/Zn0.9Mg0.1O 多量子阱结构。通过对Si基ZnO、ZnMgO薄膜的界面能带结构研究及应力、缺陷分析，揭示了Lu2O3不仅作为Si衬底上外延ZnO薄膜的缓冲层，而且还是电子空穴的有效势垒层。实验首次发现Na在ZnO中存在两个受主能级，并揭示了Na受主的失活过程以及Na掺杂的极性调控特性，对p型掺杂机理有了更深入理解。上述研究对Si基ZnO光电器件的设计及发展具有重要的指导意义。本项目的相关研究成果发表在有影响力的国际期刊上，包括SCI论文28篇（影响因子IF大于3的14篇）、授权国家发明专利3项、申请国家发明专利10项，达到项目预期目标。