In this work, the modeling of a vertical double-junction silicon solar cell is presented. The main focus is on comparing the device characteristics and performance parameters when a tunnel junction or a metal layer is used as the interface between the subcells. The advantages and limitations of the fabrication technologies for vertical solar cells that include a tunnel junction or a metal interlayer as the contact between the subcells are discussed. For the tunnel junction-based structure, the simulation framework and the set of parameters used in the modeling are described in detail. By fitting the simulated and experimental I-V characteristics of the tunnel junction, the following parameters were extracted: effective masses at the band edges mc=0.212m0, mv=0.178m0, as well as the Huang-Rhys coefficient S=1.29. Comparative results for the dependence of the conversion efficiency on solar concentration are also presented. It is shown that for the considered geometric dimensions, the efficiency differences between the analyzed device configurations are minimal. For both types of solar cells, the conversion efficiency increases almost linearly with solar concentration up to approximately 200 suns, reaches a saturation region, and then starts to decrease at concentrations above approximately 500 suns.
