Device model for intermediate band materials
Eduard C. Dumitrescu1, Matthew M. Wilkins1,2, Jacob J. Krich1,2
1Department of Physics, University of Ottawa, Ottawa, ON, Canada
/2School of Electrical Engineering and Computer Science, Ottawa, ON, Canada

Device modeling is an essential part of the design of all semiconductor devices. Though many device models exist for semiconductors, there has not been any that can treat the optical, transport, and trapping processes of intermediate band (IB) materials, which have an extra band of allowed electronic states deep inside the semiconductor bandgap. We demonstrate Simudo, a new open source finite element device model for two-dimensional IB devices, with support for semiconductor and IB materials. Simudo solves the coupled Poisson/drift-diffusion equations for the transport of carriers in multiple bands: the valence, conduction, and any number of intermediate bands. It uses degenerate statistics for the IB band occupancy and self-consistent optical absorption, dependent on the photofilling of the IB. We show that Simudo performance is excellent for a pn-diode structure, benchmarked against Synopsys Sentaurus.  Simudo permits simulation and optimization of IB devices and should be of immediate utility for those working on IB solar cells and photodetectors.