分子束外延生长InGaN量子点及其结构和光学特性

Structures and Optical Characteristics of InGaN Quantum Dots Grown by MBE

摘要:

采用射频等离子体辅助分子束外延 (RF-MBE)技术在蓝宝石衬底上，外延生长了发光波长位于407 nm的InGaN量子点结构，研究了InN成核层技术对其结构和光学特性的影响。材料生长过程中采用反射式高能电子衍射 (RHEED)进行了在位检测，通过原子力显微镜 (AFM)，光致发光 (PL)等测试手段表征了InGaN量子点材料的结构和光学特性。结果表明，相对于直接在GaN层上自组织生长InGaN量子点，通过InN成核层技术可以获得高密度、高质量的InGaN量子点结构，量子点尺寸分布更加均匀，主要集中在35~45 nm之间；量子点的密度更高，可以达到3.2×1010/cm2；InN成核层上生长的InGaN量子点的PL发光峰强度为直接在GaN层上生长的InGaN量子点的2倍，发光峰的半高宽较窄，为10 nm

Abstract:

InGaN quantum dots were grown on sapphire substrate by radio-frequency plasma-excited molecular beam epitaxy (RF-MBE). The effects of InN nuclear layer on the structural and optical characteristics of InGaN quantum dots were studied. In-situ reflection high energy electron diffraction (RHEED) was used to analyze the growth of the InGaN dots structures. Atomic force microscope (AFM) and photoluminescence (PL) were used to characterize the structure and optical properties of the InGaN quantum dots. The results show that the InGaN quantum dots grown on the InN nuclear layer can get higher density and better quality compared with that grown directly on GaN layer. The sizes of InGaN quantum dots grown on the InN nuclear layer are more uniform, about 35-45 nm and the density can reach 3.2 × 1010/cm2. The PL intensity of the InGaN quantum dots grown on the InN nuclear layer is twice as high as that of the InGaN quantum dots grown directly on GaN layer. The FWHM of the quantum dots PL peak is about 10 nm