生长温度对In0.5Ga0.5As/GaAs量子点尺寸的影响
Effect of Growth Temperature on Size of In0.5Ga0.5As/GaAs Quantum Dots

采用分子束外延( MBE )技术制备In0.5Ga0.5As/GaAs量子点，利用扫描隧道显微镜( STM )对不同衬底温度下生长的样品进行表征分析。研究表明量子点密度随温度升高先增大后减小，其尺寸随温度的升高而增大。另外，量子点以S-K模式生长并受Ostwald熟化机制影响，其尺寸增大所需的能量来自应变能和温度提供的能量，高温条件下表面原子的解吸附作用会限制量子点的生长。
The In0.5Ga0.5As/GaAs quantum dots (QDs) were prepared by the technique of molecular beam epitaxy (MBE), Scanning tunneling microscope (STM) was used to characterize the samples grown at different growth temperature. The results show that the densities of the In0.5Ga0.5As/GaAs QDs increase first and then decrease, and the sizes increase with the increase of temperature. Besides, this work demonstrates that the growth mode of QDs is affected by curing mechanism of Ostwald. The energy that needed for the sizes increase is provided by strain energy and temperature, however, the growth of QDs is limited by the desorption of surface adatoms at high temperature .