Nanopatterning of GaAs(110)vicinal surfaces by hydrogen-assisted MBE

摘要

The effect of atomic hydrogen on the growth mode and surface morphology of GaAs(l 10)thin films grown by molecular beam epitaxy(H-MBE)has been studied for different kinetic regimes using atomic force microscopy(AFM).Growth in the Ga supply-limited regime after H-assisted oxide removal leads to the formation of multi-atomic step arrays by step bunching with a very uniform terrace size distribution in the 80 nm range.Growth under As-deficient conditions after H-assisted oxide removal induces a rapid self-organization of the GaAs(l 10)surface into a ridge pattern along the <001> tilt direction,which is broken down into a 3D mound morphology when H is also present during growth.A chacteristic nanofacetting of the surface with very straight -type steps is observed at high temperatures regardless of atomic hydrogen being used during oxide desorption and/or epitaxial growth.