STM and RHEED study of InAs/GaAs quantum dots obtained by submonolayer epitaxial techniques

Formation of uniform arrays of InAs quantum dots on GaAs(100) singular and vicinal (3 degrees towards [011] direction) surfaces crucially depends on the deposition mode chosen. For dots formed with continuous As flux impinging on the surface and simultaneous submonolayer In deposition cycles, intentional substrate misorientation significantly decreases the density of dots and stimulates their ordering along the [001] direction. On the contrary, growth using alternate In and As deposition cycles results in a reduced density of dots for singular surfaces and in strongly increased dot concentration for vicinal ones. Ordering of dots in chains along [001] and [010] directions is observed for the alternative deposition on singular substrates.