title: Characterization and density control of GaN nanodots on Si (111) by droplet epitaxy using plasma-assisted molecular beam epitaxy.
abstract: In this report, self-organized GaN nanodots have been grown on Si (111) by droplet epitaxy method, and their density can be controlled from 1.1 × 10(10) to 1.1 × 10(11) cm(-2) by various growth parameters, such as substrate temperatures for Ga droplet formation, the pre-nitridation treatment of Si substrate, the nitridation duration for GaN crystallization, and in situ annealing after GaN formation. Based on the characterization of in situ RHEED, we can observe the surface condition of Si and the formation of GaN nanodots on Si. The surface nitridaiton treatment at 600°C provides a-SiNx layer which makes higher density of GaN nanodots. Crystal GaN nanodots can be observed by the HRTEM. The surface composition of GaN nanodots can be analyzed by SPEM and μ-XPS with a synchrotron x-ray source. We can find GaN nanodots form by droplet epitaxy and then in situ annealing make higher-degree nitridation of GaN nanodots.
authors.affiliation: Department of Materials Science and Engineering, National Dong Hwa University, Hualien 97401, Taiwan.
authors.forename: Ing-Song
authors.initials: IS
authors.lastname: Yu
authors.affiliation: Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan.
authors.forename: Chun-Pu
authors.initials: CP
authors.lastname: Chang
authors.affiliation: Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan.
authors.forename: Chung-Pei
authors.initials: CP
authors.lastname: Yang
authors.affiliation: Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan.
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: Lin
authors.affiliation: Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan.
authors.forename: Yuan-Ron
authors.initials: YR
authors.lastname: Ma
authors.affiliation: National Nano Device Laboratories, Hsinchu 30078, Taiwan.
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Chen
keywords: Droplet epitaxy; Gallium nitride; Molecular beam epitaxy; Quantum dots; Reflection high-energy electron diffraction; Scanning photoemission microscopy; X-ray photoelectron spectroscopy