ABSTRACT
This chapter provides a brief introduction to opportunities and challenges provided by nanowire heterostructures. It explores basic concepts in the growth and structure of epitaxial heterostructure nanowires and outlines goals for controlling structure and composition. The chapter describes relationships between structures and properties and provides select examples of nanowire devices with an emphasis on electrical and optical devices. Epitaxial nanowire heterostructures enable crystal growers to transcend limitations of conventional thin-film heterostructures to create new opportunities for device engineering. In axial heterostructures, heterointerfaces are perpendicular to the nanowire growth axis. Nanowires are the result of highly anisotropic crystal growth driven by preferential nucleation on a single facet or set of facets. The major goals of nanowire heterostructure growth are to control position, orientation, and crystallinity. Heterostructures within nanowires can be formed either along or perpendicular to the nanowire growth direction. The general goals for impurity doping are to selectively dope portions of nanowire heterostructures and to limit undesirable diffusion of dopants.
