Magnetotransport potentials for anisotropic thin films with stripline and ground plane contacts

摘要

Superlattice layers in infrared emitters and detectors can be highly anisotropic in their electrical properties, and proper characterization of their in-plane and cross-plane transport can reveal information about the band structure, doping density, impurities, and carrier lifetimes. This work introduces numerical simulation methods for the potential distribution in an anisotropic resistive layer representing a superlattice, using both and non-conformal and conformal mapping to simplify the calculation of the potential in the presence of a magnetic field. A single strip-line contact is modeled atop the resistive superlattice layer of interest, which, in turn, contacts with a highly conducting back-plane. The Laplace equation is solved numerically to deduce the potential distribution in a magnetic field, with Dirichlet boundary conditions at the grounded back-plane and magnetic field-dependent Neumann boundary conditions at the floating front-plane. To increase computational efficiency, non-conformal and conformal mapping are combined to transform the problem of an intractable infinitely wide anisotropic thin-film sample to a calculable, finite isotropic rectangular shape. The potential calculations introduced here should prove useful for deducing the full conductivity tensor of the superlattice region, including in-plane, cross-plane, and transverse conductivity tensor components.