【摘要】 采用分子束外延方法在GaAs(331)A高指数衬底上制备自对齐InAs量子线(QWR)或者三维(3D)岛状结构。InAs量子线(QWR)选择性生长在GaAs层的台阶边缘。通过原子力显微镜(AFM)仔细研究了InAs纳米微结构的表面形貌,发现不同的生长条件如衬底温度、生长速率和InAs层厚度等,对InAs表面形貌有很大的影响。低温更容易导致线状纳米微结构的形成,而高温更利于3D岛状结构形成。表面形貌的转变归结于表面能同应变能之间的竞争。更多还原

【Abstract】 Self-aligned InAs quantum wires (QWRs) or three-dimensional (3-D) islands are fabricated on GaAs(331)A substrates by molecular beam epitaxy (MBE). InAs QWRs are selectively grown on the step edges formed by GaAs layers. The surface morphology of InAs nanostructures is carefully investigated by atomic force microscopy (AFM) measurements. Different growth conditions, such as substrate temperature, growth approach and InAs coverage, exert a great effect on the morphology of InAs islands. Low substrate temperatures prefer to the formation of wire like nanostructures while high substrate temperatures favor for 3-D islands. The shape transition is attributed to the tradeoff between surface energy and strain energy.更多还原