Novel Characterization Methods for Anisotropic and Mixed-Conduction Materials

Modern electronic and optoelectronic devices consist of active layers with multiple charge carriers and anisotropic band structure, requiring new characterization methods to separate out individual carrier contributions to the anisotropic conductivity tensor. In this research, we will develop novel methods for sorting the multiple charge contributions, as well as separating out individual conductivity tensor components. Such techniques include mobility spectrum analysis for sorting electrons and holes of different mobilities, the 3 x 3 ground-plane method for determining anisotropic conductivity tensor components of a thin film on a highly conducting substrate, and density gradient analysis for extracting density gradients in bulk-doped and modulation doped heterostructures. These techniques will be tested on technologically relevant anisotropic electronic and optoelectronic materials, such as quantum cascade lasers, type II interband cascade lasers, type II superlattice infrared photodetectors, transverse thermoelectric materials, and inhomogeneously doped quantum wells.