title: Novel heterostructured Ge nanowires based on polytype transformation.
abstract: We report on a strain-induced phase transformation in Ge nanowires under external shear stresses. The resulted polytype heterostructure may have great potential for photonics and thermoelectric applications. ⟨111⟩-oriented Ge nanowires with standard diamond structure (3C) undergo a phase transformation toward the hexagonal diamond phase referred as the 2H-allotrope. The phase transformation occurs heterogeneously on shear bands along the length of the nanowire. The structure meets the common phenomenological criteria of a martensitic phase transformation. This point is discussed to initiate an on going debate on the transformation mechanisms. The process results in unprecedented quasiperiodic heterostructures 3C/2H along the Ge nanowire. The thermal stability of those 2H domains is also studied under annealing up to 650 °C by in situ TEM.
authors.affiliation: Univ. Paris-Sud, Institut d'Electronique Fondamentale , UMR 8622, Orsay F-91405, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Vincent
authors.forename: Gilles
authors.initials: G
authors.lastname: Patriarche
authors.forename: Géraldine
authors.initials: G
authors.lastname: Hallais
authors.forename: Charles
authors.initials: C
authors.lastname: Renard
authors.forename: Cyrille
authors.initials: C
authors.lastname: Gardès
authors.forename: David
authors.initials: D
authors.lastname: Troadec
authors.forename: Daniel
authors.initials: D
authors.lastname: Bouchier
mesh_terms: D005857:Germanium / Q000737:chemistry*; D006358:Hot Temperature; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure*; D033081:Shear Strength
chemical_list: D005857:Germanium