title: Atomic scale strain relaxation in axial semiconductor III-V nanowire heterostructures.
abstract: Combination of mismatched materials in semiconductor nanowire heterostructures offers a freedom of bandstructure engineering that is impossible in standard planar epitaxy. Nevertheless, the presence of strain and structural defects directly control the optoelectronic properties of these nanomaterials. Understanding with atomic accuracy how mismatched heterostructures release or accommodate strain, therefore, is highly desirable. By using atomic resolution high angle annular dark field scanning transmission electron microscopy combined with geometrical phase analyses and computer simulations, we are able to establish the relaxation mechanisms (including both elastic and plastic deformations) to release the mismatch strain in axial nanowire heterostructures. Formation of misfit dislocations, diffusion of atomic species, polarity transfer, and induced structural transformations are studied with atomic resolution at the intermediate ternary interfaces. Two nanowire heterostructure systems with promising applications (InAs/InSb and GaAs/GaSb) have been selected as key examples.
authors.affiliation: Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB , 08193 Bellaterra, Catalonia, Spain.
authors.forename: María
authors.initials: M
authors.lastname: de la Mata
authors.forename: César
authors.initials: C
authors.lastname: Magén
authors.forename: Philippe
authors.initials: P
authors.lastname: Caroff
authors.forename: Jordi
authors.initials: J
authors.lastname: Arbiol
keywords: Cs-corrected scanning transmission electron microscopy; III−V; Nanowire (NW); atomic scale; axial heterostructures; strain relaxation