SiLENSe version 6.5 has been released. New version supports simulation of heterostructures including tunnel junctions. Tunnel junctions can be used to connect different cascades of LED/LD structures or enable replacing p-contact by combination of TJ and n-contact.

The basic idea of simulating tunnel junctions is as follows. User selects several adjacent layers and creates a tunnel junction region similarly it is done for periodic structures. For each tunnel junction, dependence of the tunnel current on the bias applied to the tunnel junction is computed before start of the main computation of the whole heterostructure. During main computation, the band diagram of the whole structure is calculated, the bias applied to each tunnel junction is determined, and the respective value of the tunnel current is added into the carrier transport equations. Conventional drift-diffusion current in the tunnel junction region is also considered in the model.

Three options are available for computation of the tunnel current:
(i) Parametric dependence where user can adjust two parameters.
(ii) User-defined script function or tabulated function.
(iii) Direct simulation of the band-to-band tunneling by integrating the product of the tunneling probability, density of states, and respective combination of the Fermi distribution functions over the whole range of possible energy of tunneling carriers.