New models of clean and hydrogenated amorphous silicon surfaces
Year: 2025
Type: article
Abstract: We present new atomistic models of amorphous silicon (a-Si) and hydrogenated amorphous silicon (a-Si:H) surfaces. The a-Si model included 4096 atoms and was obtained using local orbital density functional theory. By analyzing a slab model (periodic in two dimensions with a slab about 44 Å thick), we observed a strong correlation between surface structure and surface charge density, which might be compared to STM experiments. Hydrogen atoms added near the under-coordinated surface atoms passivate dangling bonds and induce structural rearrangements. We analyze the electronic structure, including the localization of the states, and note resonant mixing between bulk and surface defect structures. We also compute the classical normal modes of the hydrogenated a-Si and compare them to experiments where possible. Our work is a step towards understanding the meaning of “surface reconstruction” for a noncrystalline material. • Developed atomistic models of a-Si and a-Si:H surfaces using local orbital DFT. • Strong correlation between surface structure and charge density, similar to STM. • DOS at Fermi level shows resonant mixing between surface and bulk structures. • Classical normal modes within Harmonic Approximation for a-Si:H is reported.
Authors: K. Nepal, A. Gautam, C. Ugwumadu, D.A. Drabold
Institutions: Ohio University, Los Alamos National Laboratory
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,380
Funder: National Science Foundation
OpenAlex ID: W4409622737