  We present a domain decomposition approach for the simulation of charge
transport in heterojunction semiconductors. The problem is characterized by a
large variation of primary variables across an interface region of a size much
smaller than the device scale, and requires a multiscale approach in which that
region is modeled as an internal boundary. The model combines drift diffusion
equations on subdomains coupled by thermionic emission heterojunction model on
the interface which involves a nonhomogeneous jump computed at fine scale with
Density Functional Theory. Our full domain decomposition approach extends our
previous work for the potential equation only, and we present perspectives on
its HPC implementation. The model can be used, e.g., for the design of higher
efficiency solar cells for which experimental results are not available. More
generally, our algorithm is naturally parallelizable and is a new domain
decomposition paradigm for problems with multiscale phenomena associated with
internal interfaces and/or boundary layers.
