摘要
Scanning tunneling microscopy was used to study surface structures and doping properties of molecular beam epitaxy (MBE)-grown Si-doped GaAs(001)-(2 × 4) and GaAs(001)-c(4 × 4) surfaces on the atomic scale. It was found that on the Si-doped (2 × 4) surface, arsenic dimers formed several energetically different configurations besides the most stable two-dimer configuration. The doping properties of the c(4 × 4) surface were found to be significantly different from the (2 × 4) case. The Si dopants tended to segregate on top of the c(4 × 4) surface and formed small asymmetric clusters oriented along the [110] direction.