中文摘要：

采用反射高能电子衍射仪与扫描隧道显微镜技术对GaAs（001）-（2×4）表面重构下的表面形貌进行深入研究，获得GaAs（001）薄膜处于不同（2×4）表面重构时的表面形貌。研究发现当GaAs（001）表面处于β2（2×4）时，经过精确控制薄膜的生长、退火以及淬火工艺，GaAs（001）表面能够获得由单一重构组成且原子级平坦的表面形貌；研究结果证实胆（2×4）的表面重构原胞中存在三对AsDimers，其中两对位于重构原胞顶层，一对处于重构原胞次层，这与球棍模型理论下获得的β2（2×4）重构原胞高度吻合；研究发现γ（2×4）表面重构实际上是β2（2×4）重构与C（4×4）重构混合后的重构形式，γ（2×4）重构表面是由大量单层岛和单层坑混合后的无序平坦表面；α（2×4）存在的温度区间很窄，它是GaAs表面从富As状态到富Ga状态转变的过渡重构形式，实验中将很难获得单-α（2×4）重构相表面。

英文摘要：

The GaAs（001 ）-（2 × 4）reconstructed surfaces were characterized with reflection high energy electron diffra fion（ RHEED ）, and scanning tunneling microscopy（STM）. Distinctive difference was observed between GaAs（001 ）- β2（2 × 4） and γ （2 × 4） reconstructionsThe well-defined GaAs （ 001 ）-β2 （ 2 × 4） reconstruction on atomically flat surface can be prepared routinely by synthesizing, annealing, and quenching under the optimized conditions. The results show that the unit-cell in β2（2× 4） reconstruction can be described with three As-dimers,two in the top layer and one in the sec-ond layer, in consistent with the unit cell of β2（2 × 4） reconstruction calculated with the ball-and-stick model. The γ（2 × 4）reconstruction was found to originate from a mixture of β2（2 × 4）and c（4× 4）reconstruction on the fiat surfaces with a large number of randomly distributed mono-layered islands and pits. The α（2 × 4）reconstruction was rarely observed pos-sibly because its existing temperature range was too narrow and because it involved a transition from As-rich to Ga-rich phases.