A transferable full-band Monte Carlo framework for complex alloy avalanche photodiodes
Abstract
We present a physics-based multiscale full-band Monte Carlo framework for modeling avalanche multiplication and excess noise in complex alloy avalanche photodiodes (APDs), demonstrated on Al0.7InAsSb as a representative quaternary system. The framework links atomistic material structure to device-level avalanche statistics: an environment-dependent sp3d5s∗ tight-binding calculation resolves the full conduction- and valence-band structure of the random- or digital-alloy configuration -- including Γ, X, and L valley ordering, non-parabolicity, anisotropy, and spin-orbit-induced valence-band splitting -- and supplies the band-structure inputs for stochastic high-field transport. A central element of the framework is a physics-derived treatment of alloy-disorder scattering, in which the quaternary disorder potential is constructed from atomic valence differences, covalent radii, and Thomas--Fermi screening through a composition-weighted decomposition into binary contributions, complemented by composition-interpolated polar-optical, acoustic, intervalley-phonon, impurity, and impact-ionization models. Because every material-dependent input is generated from the atomic composition and configuration by the same well-defined procedure, the framework transfers without structural modification to arbitrary zinc-blende ternary and quaternary alloys. Applied to a \SI{1}{\micro\meter} Al0.7InAsSb p-i-n APD, the framework reproduces the measured gain and excess-noise characteristics with only the impact-ionization softness parameters calibrated. The approach provides a documented, reproducible route for analyzing and designing complex alloy APDs in which band structure, disorder, and scattering physics jointly determine gain and ionization statistics.
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BibTeX
@misc{shahnewaz2026transferable,
title = {{A transferable full-band Monte Carlo framework for complex alloy avalanche photodiodes}},
author = {Shafat Shahnewaz and Hannaneh Karimi and Joe C. Campbell and Avik W. Ghosh},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.39795},
eprint = {2609.39795},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.39795},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A transferable full-band Monte Carlo framework for complex alloy avalanche photodiodes
AU - Shafat Shahnewaz
AU - Hannaneh Karimi
AU - Joe C. Campbell
AU - Avik W. Ghosh
PY - 2026
DA - 2026/09/30
PB - arXiv
DO - 10.48550/arxiv.2609.39795
UR - https://arxiv.org/abs/2609.39795
AB - We present a physics-based multiscale full-band Monte Carlo framework for modeling avalanche multiplication and excess noise in complex alloy avalanche photodiodes (APDs), demonstrated on Al_0.7InAsSb as a representative quaternary system. The framework links atomistic material structure to device-level avalanche statistics: an environment-dependent sp^3d^5s^∗ tight-binding calculation resolves the full conduction- and valence-band structure of the random- or digital-alloy configuration -- including Γ, X, and L valley ordering, non-parabolicity, anisotropy, and spin-orbit-induced valence-band splitting -- and supplies the band-structure inputs for stochastic high-field transport. A central element of the framework is a physics-derived treatment of alloy-disorder scattering, in which the quaternary disorder potential is constructed from atomic valence differences, covalent radii, and Thomas--Fermi screening through a composition-weighted decomposition into binary contributions, complemented by composition-interpolated polar-optical, acoustic, intervalley-phonon, impurity, and impact-ionization models. Because every material-dependent input is generated from the atomic composition and configuration by the same well-defined procedure, the framework transfers without structural modification to arbitrary zinc-blende ternary and quaternary alloys. Applied to a \SI{1}{\micro\meter} Al_0.7InAsSb p-i-n APD, the framework reproduces the measured gain and excess-noise characteristics with only the impact-ionization softness parameters calibrated. The approach provides a documented, reproducible route for analyzing and designing complex alloy APDs in which band structure, disorder, and scattering physics jointly determine gain and ionization statistics.
ER -