【摘要】 运用透射电子显微术(TEM)对由分子束外延(MBE)制备的GaAs InGaAs多层量子点样品进行观察和分析。利用对量子点周围应变场分布的模拟,定性解释了量子点形貌及其周围发现的凹陷区域。通过对量子点高分辨像显示的晶格错配和化学成分分析研究,解释了所研究样品中量子点尺寸逐层增大的现象。研究结果为量子点材料生长过程中应变场的控制提供了一些思路。更多还原

【Abstract】 GaAs/InGaAs quantum dots grown by molecular beam epitaxy (MBE) were studied. Trenches were found at the bottom of quantum dots in the specimens, it was attributed to abnormal strain distribution by the simulation of strain field around one quantum dot. The analysis on the lattice mismatch, chemical composition distribution and interplanar spacing of {111} in the specimens by analytical electron microscopy has been carried out. And related with the amount of indium in each layer and the thickness of spacer layer, a size increasing of the quantum dot along the growth direction was explained.更多还原