I'm not sure but I thin that related to the SOPRA file if this material is already defined by SILVACO (not user-defined), or you have to define it by yourself using a file includes a refractive and extinction indexes n,k. because the absorption coefficient is related to these parameters.
Have you simulated quantum dot solar cells in silvaco?
Is it possible? I have seen only quantum wells...is it possible to simulate quantum dot as well? I'm working on QD solar cell simulations in silvaco and having some difficulties.