2020/11/28 by Reza Vatan Meidanshahi, Meidanshahi, Reza Vatan, Stephen M. Goodnick +3
Engineering · Physics and Astronomy · #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Semiconductor materials and devices #Semiconductor materials and interfaces #Thin-Film Transistor Technologies
paper · pdf · doi:10.48550/arxiv.2011.14158
openalex publication_date 2020/11/28 · openalex created_date 2020/12/07 · openalex updated_date 2026/07/28
In this paper, we explore the effect of H and its bonding configurations on the defect state density and orbital localization of hydrogenated amorphous Si (a-Si:H)/crystalline Si (c-Si) heterostructures using density functional theory (DFT) studies of model interfaces between amorphous silicon (a- Si)/a-Si:H and c-Si. To model the atomic configuration of a-Si on c-Si, melting and quenching simulations were performed using classical molecular dynamics (MD). Different hydrogen contents were inserted into the a-Si in different bonding configurations followed by DFT relaxation to create the stable structures of a-Si:H representative of hydrogenated a-Si on crystalline Si surfaces. In contrast to crystalline heterojunctions (where the interface density is a maximum at the interface), we find that, in the most energetically stable configurations of H atoms, the defect state density is relatively low at the interface and maximum at the middle of a-Si layer. Our structural analysis shows that in these configurations, H atoms do not necessarily bond to dangling bonds or to interface atoms. However, they are able to significantly change the atomic structure of the heterostructure and consequently decrease the density of defect states and orbital localization at the a-Si layer and more significantly at the interface of a-Si/c-Si. The general form of the modeled defect state distribution demonstrates the passivating role of a-Si:H on c-Si substrates.