Characterization of anti-phase boundaries at a GaP/Si(001) cross-sectional surface on the atomic scale

We report on a cross-sectional scanning tunneling microscopy (XSTM) investigation of anti-phase boundaries on epitaxial grown GaP layers on a Si(001) substrate. The growth conditions of the GaP layer was chosen to produce a significant anti-phase disorder, to favor the XSTM experiment. A different image contrast for the main phase and the anti-phase domain within the GaP layer could be observed. The image contrast mechanisms of anti-phase boundaries in the XSTM experiment are studied on the atomic scale. This investigation shows the feasibility of such an analysis and the perspective to reveal the atomic arrangement of the anti-phase boundaries as well as the evolution along growth direction due to the excellent surface sensitivity of this method.