采用分子束外延方法，通过RHEED 的实时监控在GaAs（001）衬底上外延生长InAs量子点.利用改变生长厚度（1.7，1.8，2.0，3.0 mL），结合RHEED衍射花样与STM扫描图片，获得InAs量子点表面形貌与生长层数的对应关系，揭示了InAs/GaAs量子点的生长变化规律.研究发现，当外延InAs厚度在1.7 mL以下时样品保持平整状态，几乎没有出现任何量子点结构；当InAs外延厚度超过1.7 mL时，外延层生长模式将从2 D模式向3 D模式过渡，从而形成InAs量子点，证明1.7 mL 就是 InAs 在 GaAs 表面外延时的临界厚度；进一步增加 InAs 沉积量后（1.8，2.0，3.0 mL），量子点将通过自组装生长从逐渐增多到不断增大然后再到数量和体积都迅速增大的转变过程.%InAs/GaAs quantum dots were prepared by molecular beam epitaxy under the real - time monitoring of RHEED. Combined with RHEED patterns and STM images,the relations between sur-face morphologies and thickness of InAs epitaxy layers were found and the growth law of InAs/GaAs quantum dots was discovered. In this paper,we found that surface morphology of InAs/GaAs should keep flat when the InAs epitaxy layers less than 1 . 7 mL and no quantum dots existed;as soon as it be-yond this critical thickness,the growth mode would change from 2D to 3D mode,and then lots of quantum dots should be formed at this time. Increasing the InAs epitaxy layers to 1. 8 mL,2. 0 mL and 3. 0 mL,the InAs/GaAs quantum dots should experienced an interesting process,at first the number of quantum dots should be increased gradually,and then more deposition would augment the volume of quantum dots,at last when the InAs epitaxy layers reached 3. 0 mL,the number and volume of quan-tum dots would be increased rapidly.
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