1,173 research outputs found
Numerical methods for drift-diffusion models
The van Roosbroeck system describes the semi-classical transport of
free electrons and holes in a self-consistent electric field using a
drift-diffusion approximation. It became the standard model to describe the
current flow in semiconductor devices at macroscopic scale. Typical devices
modeled by these equations range from diodes, transistors, LEDs, solar cells
and lasers to quantum nanostructures and organic semiconductors. The report
provides an introduction into numerical methods for the van Roosbroeck
system. The main focus lies on the Scharfetter-Gummel finite volume
disretization scheme and recent efforts to generalize this approach to
general statistical distribution functions
Diffusive Transport in Quasi-2D and Quasi-1D Electron Systems
Quantum-confined semiconductor structures are the cornerstone of modern-day
electronics. Spatial confinement in these structures leads to formation of
discrete low-dimensional subbands. At room temperature, carriers transfer among
different states due to efficient scattering with phonons, charged impurities,
surface roughness and other electrons, so transport is scattering-limited
(diffusive) and well described by the Boltzmann transport equation. In this
review, we present the theoretical framework used for the description and
simulation of diffusive electron transport in quasi-two-dimensional and
quasi-one-dimensional semiconductor structures. Transport in silicon MOSFETs
and nanowires is presented in detail.Comment: Review article, to appear in Journal of Computational and Theoretical
Nanoscienc
Multi-dimensional modeling and simulation of semiconductor nanophotonic devices
Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources
Modelling and simulation of advanced semiconductor devices
This paper presents a modelling and simulation study of advanced semiconductor devices. Different Technology Computer Aided Design approaches and models, used in nowadays research are described here. Our discussions are based on numerous theoretical approaches starting from first principle methods and continuing with discussions based on more well stablished methods such as Drift-Diffusion, Monte Carlo and Non-Equilibrium Green’s Function formalism
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