A Combined Classical Molecular Dynamics Simulations and AB Initio Calculations Approach to Study A-SI:H/C-SI Interfaces

Abstract

In the silicon heterojunction solar cells, intrinsic hydrogenated amorphous silicon a-Si:H is used to passivate the crystal silicon c-Si surface to suppress the electrical losses at interfaces and to keep ultralow contact resistivity for the selective transport of one type of carrier only. We use ReaxFF (Reactive Force Field) molecular dynamics to efficiently simulate the thermalisation, quenching, and equilibration processes involving thousands of atoms forming realistic a-Si:H/c-Si interface structures. We generated snapshots of the equilibrated c-Si/a-Si:H interface atom configurations at room temperature. The ab initio characterization has been executed on selected configurations to monitor the electronic properties of the c-Si/a-Si:H interface. The evolution of the intragap states is monitored by analyzing density of states and charge density. This all will allow to design more efficient silicon solar cells belonging to the silicon heterojunction technology.