SCANNING TUNNELING MICROSCOPY ON MOLECULAR-BEAM-EPITAXY-GROWN GAAS(001) SURFACES

Molecular-beam-epitaxy(MBE)-grown GaAs(001) As-stabilized surface morphology has been in-situ observed by scanning tunneling microscopy (STM). A multichamber S(R)EM-MBE-STM system has been developed. The correspondence between reflection high-energy electron diffraction (RHEED) oscillation and two-dimensional nucleation has first been verified by STM on vicinal GaAs surfaces tilted from (001) toward [110BAR) direction. Moreover, STM observations of GaAs surfaces grown at high temperature with a slow growth rate on exactly oriented substrates reveal terraces with an area of more than 200 nm2, which is the largest reported to date. STM has manifested itself to be indispensable in the development of atomic-level controlled-growth technologies for quantum-effect devices.