Top 1011 Videos

MM02 – Carrier transport in (In,Ga)N quantum well systems: Connecting atomistic tight-binding electronic structure theory to drift-diffusion simulations

O’Donovan M., Farrell P., Streckenbach T., Koprucki T., Schulz S.

Understanding the impact of the alloy microstructure on carrier transport in (In,Ga)N/GaN quantum well systems is important for aiding device design. We study the impact that alloy fluctuations have on uni-polar carrier transport for both electrons (n-i-n junction) and holes (p-i-p junction) using a multiscale framework. To do so we connect an atomistic tight-binding model […]

D01 – Non-Uniform Time-Stepping For Fast Simulation of Photodetectors Under High-Peak-Power, Ultra-Short Optical Pulses

Simsek E., Anjum I. Md, Carruthers T. F., Menyuk C. R.

A novel non-uniform time-stepping procedure is developed to reduce the memory usage and simulation time—by two orders of magnitude—of photodetectors when detecting high-peak-power, ultra-short optical pulses. The proposed procedure can be used in other marching-on-in-time solvers to achieve the same for the simulations dealing with ultra-short pulses.

LD04 – Modeling carrier transport in mid-infrared VCSELs with type-II superlattices and tunnel junctions

Torrelli V., Montoya J. A. G., Tibaldi A., Debernardi P., Simaz A., Belkin M. A., Goano M., Bertazzi F.

Vertical-cavity surface-emitting lasers are promising light sources for sensing and spectroscopy applications in the midinfrared 3 ÷4 µm spectral region. A type-II superlattice active region is used for carrier injection and confinement, while a buried tunnel junction defines a current aperture, decreasing the series resistivity. Highly nanostructured to optimize device performance, mid-infrared VCSELs pose modeling […]

NM02 – Impact of random alloy fluctuations on the electronic and optical properties of c-plane AlxGa1−xN/AlN quantum wells

Finn R., Schulz S.

We present a theoretical study of the electronic and optical properties of c-plane AlxGa1−xN/AlN quantum wells emitting in the ultraviolet-A (UV-A) to UV-C spectral range. Special attention is paid to the impact of alloy fluctuations on the results. We find that random alloy fluctuations in (Al,Ga)N are already sufficient to cause strong carrier localization effects. […]

MM04 – Simulation of ac conductivity of monolayer MoS2 at terahertz frequencies

Mitra S.,

We present a multiphysics numerical tool for calculating the terahertz (THz) conductivity of transition-metal dichalcogenides (TMDs). The tool combines the ensemble Monte Carlo (EMC) technique for carrier transport with a three-dimensional finite-difference-time-domain (FDTD) solver for electromagnetic fields. We use the coupled EMC–FDTD technique to calculate the frequency-dependent conductivity in the terahertz range for monolayer MoS2, […]

LD06 – Relative intensity noise of injection-locked epitaxial quantum dot laser on silicon

Chu Q., Zhao S., Grillot F., Wang J., He F., Zhang M., Xu X., Yao Y., Duan J.

This work investigates the relative intensity noise (RIN) characteristics of quantum dot (QD) lasers epitaxially grown on silicon subject to the optical injection. The effect of threading dislocation (TD), which acts as nonradiative recombination centers in the Shockley-Read-Hall (SRH) process, is considered in the rate equation model. The results reveal that the RIN is enhanced […]

LD05 – Data-Driven Modeling of Non-Markovian Noise in Semiconductor Lasers

Mertenskötter L., Kantner M.

Non-Markovian noise degrades the coherence properties of semiconductor lasers and contributes significantly to broadening of the linewidth. Since modeling of such colored noise systems from first principles is not accessible, we aim for a data-driven modeling approach in which a system of stochastic rate equations shall be reconstructed from time series data.

MM05 – Comparison of flux discretizations for varying band edge energies

Moatti J., Farrell P.

Recently, a multiscale framework was developed where drift-diffusion is combined with atomistic tight-binding models. A naive flux discretization was proposed to tackle the problem of heavily fluctuating band edge energies which does not take into account mathematical complications. Here we would like to present several alternatives and compare them.

N02 – Influence of random alloy fluctuations on the electronic properties of axial In(x)Ga(1−x)N/GaN nanowire heterostructures

Marquardt O., Koprucki T., O’Donovan M., Schulz S., Brandt O.

Compound semiconductor heterostructures such as quantum dots, nanowires, or thin films, are commonly subject to randomly fluctuating alloy compositions if they contain ternary and quaternary alloys. These effects are obviously of an atomistic nature and thus rarely considered in heterostructure designs that require simulations on a continuum level for theory-guided design or interpretation of observations. […]