Equilibrium Analysis of Lattice-Mismatched Nanowire Heterostructures

E. Ertekin, Department of Materials Science and Engineering, University of California, Berkeley
P. A. Greaney, Department of Materials Science and Engineering, University of California, Berkeley
Timothy D. Sands, Birck Nanotechnology Center, School of Materials Engineering, and School of Electrical and Computer Engineering, Purdue University
D. C. Chrzan, Department of Materials Science and Engineering, University of California, Berkeley

Abstract

The quality of lattice-mismatched semiconductor heterojunctions is often limited by the presence of misfit dislocations. Nanowire geometries offer the promise of creating highly mismatched, yet dislocation free heterojunctions. A simple model, based upon the critical thickness model of Matthews and Blakeslee for misfit dislocation formation in planar heterostructures, illustrates that there exists a critical nanowire radius for which a coherent heterostructured nanowire system is unstable with respect to the formation of misfit dislocations. The model indicates that within the nanowire geometry, it should be possible to create perfect heterojunctions with large lattice-mismatch.