Electronic states at misfit dislocations in partially relaxed InGaAs/GaAs heterostructures

Electronic properties of strain-induced dislocations in partially relaxed InGaAs/GaAs heterostructures with a small lattice mismatch have been studied by means of deep-level transient spectroscopy (DLTS). DLTS investigations carried out with Schottky contacts revealed one deep electron trap, at about EC−0.57 eV. The trap has been attributed to electron states associated with α misfit dislocations lying at the interface between the epilayer and the substrate. Thorough studies including DLTS-line shape, DLTS-line behaviour analysis as well as capture kinetics and deep profile measurements made possible to specify the type of electronic states associated with dislocations. We relate the electron trap to “localized” states at misfit dislocations.