Correlation of a-Si:H properties with hydrogen distribution

Hydrogenated amorphous silicon (a-Si:H) has been the subject of considerable studies in the past 30 years, due to its growing application in large area optoelectronic devices, and especially in solar cells (see, for instance). In particular, the microscopic details of disordering, hydrogen migration and bonding within the amorphous silicon network are crucial for the understanding of a-Si:H, including the detrimental Staebler-Wronski (SW) effect, and for the improvement of the overall quality of the material. The authors have recently developed and applied ab-initio Molecular Dynamics (AIMD) based computational tools in order to prepare and characterize "realistic" a-Si:H structures, which were used to simulate a variety of processes and to access their microscopic details. The goal of the current research is to extend the AIMD simulation to the derivation of the electronic density of states (DOS) and correlate the "goodness" of the material with hydrogen distribution. This work is a preliminary step to the simulation of technologically and fundamentally important hydrogen diffusion and silicon dangling bonds (DB) passivation processes.