title: Strain field mapping of dislocations in a Ge/Si heterostructure.
abstract: Ge/Si heterostructure with fully strain-relaxed Ge film was grown on a Si (001) substrate by using a two-step process by ultra-high vacuum chemical vapor deposition. The dislocations in the Ge/Si heterostructure were experimentally investigated by high-resolution transmission electron microscopy (HRTEM). The dislocations at the Ge/Si interface were identified to be 90° full-edge dislocations, which are the most efficient way for obtaining a fully relaxed Ge film. The only defect found in the Ge epitaxial film was a 60° dislocation. The nanoscale strain field of the dislocations was mapped by geometric phase analysis technique from the HRTEM image. The strain field around the edge component of the 60° dislocation core was compared with those of the Peierls-Nabarro and Foreman dislocation models. Comparison results show that the Foreman model with a = 1.5 can describe appropriately the strain field around the edge component of a 60° dislocation core in a relaxed Ge film on a Si substrate.
authors.affiliation: College of Science, Inner Mongolia University of Technology, Hohhot, China.
authors.forename: Quanlong
authors.initials: Q
authors.lastname: Liu
authors.forename: Chunwang
authors.initials: C
authors.lastname: Zhao
authors.forename: Shaojian
authors.initials: S
authors.lastname: Su
authors.forename: Jijun
authors.initials: J
authors.lastname: Li
authors.forename: Yongming
authors.initials: Y
authors.lastname: Xing
authors.forename: Buwen
authors.initials: B
authors.lastname: Cheng
mesh_terms: D000465:Algorithms; D005857:Germanium / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry*
chemical_list: D005857:Germanium; D012825:Silicon