Dislocation displacement field at the surface of InAs thin films grown on GaAs(110)

Scanning tunneling microscopy topographic images have been used to obtain the dimensions of the strain Field detected at the surface of InAs thin films grown on GaAs(110) substrates by molecular-beam epitaxy. The displacement of atoms in the film due to the edge dislocation strain field has been obtained by measuring the depth and lateral dimensions of the surface response as a function of InAs thickness (less than or equal to 30 hit), Several models based on elasticity theory are used in an attempt to reproduce the experimental measurements. Only models containing a free epitaxial layer surface produce good quantitative agreement and the experimentally observed decrease in vertical displacement is found to be largely a consequence of strain held superposition due to the increasing width of the strain field originating from adjacent dislocations. [S0163-1829(98)06538-5].