带有石墨烯插入层的氮极性InGaN基红光LED制备研究

新型显示技术Micro-LED面临的挑战之一是缺乏高效可靠的红光微型芯片。虽然InGaN是制备红光微型芯片的理想材料，但InGaN基红光LED的发光效率仍然较低，限制了其应用发展。主要原因有两方面：一是高In组分InGaN的生长温度较低，导致其晶体质量差；二是高In组分InGaN量子阱中残余应力大，降低了In原子并入。针对上述问题，本项目提出研制带有石墨烯插入层的氮极性InGaN基红光LED。与常用的金属极性材料相比，氮极性InGaN有利于In原子并入且能实现更高温度下的外延生长。此外，石墨烯以sp2杂化轨道成键，与外延薄膜间作用力弱，以它作为插入层可缓解异质外延中产生的应力，进一步提高InGaN中In原子并入。因此，氮极性InGaN与石墨烯结合将有利于高In组分InGaN外延生长，进而实现InGaN基红光LED制备。本项目将为高效氮化物红光LED研究发展奠定理论与实验基础。

One of the challenges faced by the new display technology Micro-LED is the lack of efficient and reliable red microchips. Although InGaN is an ideal material for preparing the red microchips, the luminous efficiency of the high indium content InGaN based red LEDs is still low, which limits its development and application. The main reasons are as follows: (1) The growth temperature of high indium content InGaN is low, resulting in the poor crystalline quality; (2) The residual stress in the high indium content InGaN quantum well is huge, making the low indium incorporation rate in the quantum well layer. In response to these difficulties mentioned above, we propose to develop nitrogen-polar InGaN based red LEDs with graphene interlayer. Compared with the commonly used metal-polar materials, nitrogen-polar InGaN material facilitates the incorporation of indium atoms and enables epitaxial growth at higher temperature. In addition, graphene forms bonds with sp2 hybrid orbitals, and the interaction force between graphene and overgrown nitride film is weak. Using it as an interlayer can relieve the stress generated during the heteroepitaxy, and further increasing the indium atoms incorporation in InGaN. Hence, the combination of nitrogen-polar InGaN and graphene materials is benefits for the epitaxial growth of high indium content InGaN, thereby realizing the fabrication of InGaN based red LEDs. This project will lay the theoretical and experimental bases for the research and development of high-efficiency nitride red LEDs.