Numerical modelling of infrared detectors: state of the art and open problems

Numerical simulation methodologies and tools, especially those that enable three-dimensional analysis, have been critical to guide the design process of IR detector arrays. Drift-diffusion, particle based Monte Carlo, and quantum transport approaches have been used to understand detector operation and elucidate physical phenomena that can lead to significant improvement of device performance. All these modelling methodologies solve what it is referred to as the forward problem. In other words, given a device architecture and material properties, device performance is computed. Furthermore, some of these simulation methodologies are computationally demanding and, while useful to study the device physics, they need to be judiciously used for the process of device optimization. Finally, current simulation methodologies are not suitable to tackle the so called inverse problem, namely given a set of performance requirements, determine the device architecture and material properties to achieve them. This manuscript will present the state-of-the-art in simulation methodologies currently employed to design and analyze arrays of photovoltaic and superlattice (SL) based detectors, avalanche photodiodes and novel quantum structures. The limitations of each approach will be presented and possible improvement strategies outlined.