# Simudo: a device model for intermediate band materials

## TL;DR

Simudo is a novel free device modeling tool using finite element methods to simulate intermediate band materials, offering higher convergence rates and extensibility for semiconductor device analysis.

## Contribution

It introduces the first freely available FEM-based device model capable of simulating intermediate band materials with robust convergence.

## Key findings

- Simudo converges faster and more accurately than Synopsys Sentaurus on benchmark tests.
- It effectively models complex semiconductor phenomena with high numerical stability.
- The tool is designed for extensibility to include various physical processes.

## Abstract

We describe Simudo, a free Poisson/drift-diffusion steady state device model for semiconductor and intermediate band materials, including self-consistent optical absorption and generation. Simudo is the first freely available device model that can treat intermediate band materials. Simudo uses the finite element method (FEM) to solve the coupled nonlinear partial differential equations in two dimensions, which is different from the standard choice of the finite volume method in essentially all commercial semiconductor device models. We present the continuous equations that Simudo solves, show the FEM formulations we have developed, and demonstrate how they allow robust convergence with double-precision floating point arithmetic. With a benchmark semiconductor pn-junction device, we show that Simudo has a higher rate of convergence than Synopsys Sentaurus, converging to high accuracy with a considerably smaller mesh. Simudo includes many semiconductor phenomena and parameters and is designed for extensibility by the user to include many physical processes.