X-ray diffraction study on GaAs(001)-24 surfaces under molecular-beam epitaxy conditions

Takahashi, Masamitsu; Yoneda, Yasuhiro   ; Mizuki, Junichiro

The GaAs(001)- reconstructed surface was investigated by in situ surface X-ray diffraction. The sample was subjected to measurements under molecular-beam epitaxy conditions without being transferred another chamber. Several X-ray diffraction patterns were measured with increasing the substrate temperature within the -phase of GaAs(001)- in a constant As flux of 510 Torr. At relatively low temperatures up to 545C, the observed X-ray diffraction patterns agree well to the 2(24) surface. However, a different X-ray diffraction pattern was obtained at 585C, while the periodicity still persited. This change is explained by partial As-dimer desorption which results in a mixture of the 2(24) and 2(24) structures.