Growth of InAs on micro- and nano-scale patterned GaAs(001) substrates by molecularbeam epitaxy

Abstract

Molecular beam epitaxy of InAs on micro- and nano-scale patterned GaAs(001) substrateswas studied. An InAs epilayer grown on the micro-scale patterned substrate exhibits islandswith {1 1 3}-type facets, and is similar to that grown on the flat (unpatterned) substrate. Incontrast, the preferred growth of InAs on the nano-scale patterned substrate is in the direction and exhibits islands with {1 1 0}-type facets. The thickness of the dense dislocationnetworks at the interface due to strain relaxation is reduced by the micro-scale pattern incomparison with the flat substrate, while for growth on the nano-scale patterned substrate,the strain relaxes via the formation of stacking faults more than dislocations. X-raydiffraction reveals that the strains in the 300 nm InAs epilayers are nearly fullyrelaxed, and the patterns tend to decrease the lattice constants of the epilayer,implying mass transport of Ga atoms into the epilayer from the GaAs substrates.