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报道了用金属有机化学气相沉积(MOCVD)方法在蓝宝石衬底上成功地制备出GaN量子点。采用了500℃低温沉积和1050℃高温退火的两步制备法制备出密度为5×108cm-2~6×109cm-2、直径约40nm的GaN量子点。GaN量子点的密度和大小由原子力显微镜(AFM)观察测得,并由制备温度和时间所控制。观察到GaN量子点仅在高温退火后生成,这可解释为由于低温沉积,最初的沉积层中的应变能得不到释放而成为具有较高能量的中间亚稳态相,高温退火使得应变能得到释放,生成GaN量子点。
Reported the successful preparation of GaN quantum dots on a sapphire substrate by metal-organic chemical vapor deposition (MOCVD). A GaN quantum dot with a density of 5 × 108cm-2 ~ 6 × 109cm-2 and a diameter of about 40nm was prepared by a two-step preparation method of low temperature deposition at 500 ℃ and high temperature annealing at 1050 ℃. The density and size of GaN quantum dots were measured by atomic force microscopy (AFM) and controlled by the preparation temperature and time. It was observed that the GaN quantum dots were formed only after the high temperature annealing, which can be explained as that the strain in the initial deposition layer can not be released due to the low temperature deposition and becomes the intermediate metastable phase with higher energy. The high temperature annealing makes the strain energy Get released, generate GaN quantum dots.