Softening of Vibrational Modes and Anharmonicity Induced Thermal Conductivity Reduction in a-Si:H at High Temperatures

• DOI: 10.48550/arxiv.2502.05584
• Publication Date: 2025-02-08
• Authors: Zhuo Chen; Yuejin Yuan; Yanzhou Wang; Penghua Ying; Shouhang Li; Cheng Shao; Wenyang Ding; Gang Zhang; Meng An
• Keywords: Condensed Matter - Materials Science; Condensed Matter - Mesoscale and Nanoscale Physics; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences

Hydrogenated amorphous silicon (a-Si:H) has garnered considerable attention in the semiconductor industry, particularly for its use solar cells and passivation layers high performance cells, owing to exceptional photoelectric properties scalable manufacturing processes. A comprehensive understanding of thermal transport mechanism a-Si:H is essential optimizing management ensuring reliable operation these devices. In this study, we developed a neuroevolution machine learning potential based on first-principles calculations energy, forces, virial, which enables accurate modeling interatomic interactions both a-Si systems. Using homogeneous nonequilibrium molecular dynamics (HNEMD) method, systematically investigated conductivity across temperature range 300-1000 K hydrogen concentrations ranging from 6 12 at%. Our simulation results found that with at% was significantly reduced by 12% compared at 300 K. We analyzed spectral conductivity, vibrational density states lifetimes modes, revealed softening modes anharmonicity effects contribute reduction as concentration increase. Furthermore, influence diffuson propagon contribution revealed. This study provides valuable insights developing strategies silicon-based semiconducting devices advances