利用液滴外延法在GaAs(001)衬底表面制备InAs量子点,通过控制变量分别研究沉积速率、沉积量对In液滴在GaAs表面生长过程中的影响.使用原子力显微镜(Atomic Force Microscope,AFM)表征I-nAs纳米结构形貌,得出结论:(1)沉积速率主要通过影响In液滴成核率来控制液滴的密度,即随着沉积速率的增大,In原子在衬底表面的成核率增加,InAs量子点密度增加,实验符合生长动力学经典成核理论.(2)沉积量的改变主要影响液滴的熟化过程,即随着沉积量的增大,可参与生长的活跃的In原子增加,促进了液滴熟化,使得扩散坍塌的原子数量增加,导致在InAs纳米结构中出现多量子点现象.
Abstract
InAs quantum dots were prepared on the surface of GaAs(001)substrate by droplet epitaxy.The effects of deposition rate and deposition amount on the growth of In droplets on GaAs surface were studied by con-trolling variables.Atomic force microscope was used to characterize the morphology of InAs nanostructures,and it was concluded that:(1)The deposition rate mainly controls the density of the droplets by affecting the nuclea-tion rate of In droplets,that is,with the increase of the deposition rate,the nucleation rate of In atoms on the surface of the substrate increases,and the density of InAs quantum dots increases,experiments are consistent with classical nucleation theory of growth kinetics.(2)The change of deposition amount mainly affects the ripe-ning process of droplets,that is,with the increase of deposition amount,the number of active In atoms that can participate in growth increases,which promotes droplet ripening,increases the number of diffusion collapsed at-oms,and thus leads to an increase in the number of atoms in diffusion collapse.Multiple quantum dots appear in InAs nanostructures.
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