Recombination Analysis of Tunnel Oxide Passivated Contact Solar Cells

In this paper, an analytical model has been developed to observe the recombination losses involved in a tunnel oxide passivated contact solar cell with a carrier-selective layer constituting polycrystalline silicon (poly-Si). The main focus of this paper is to observe the contribution of each component of recombination current density and its effect on open-circuit voltage, V
_oc
. The effect of emitter saturation current density (Joe), surface recombination velocity, substrate thickness, and doping density of carrierselective layer on V
_oc
has been presented. The analysis indicates that V
_oc
= 766 mV can be achieved for Joe = 2 fA/cm
²
, and a doping density of poly-Si > 10
²¹
cm
^-3
in a c-Si/SiO
₂
/poly-Si contact for a 50-μm-thick substrate in case of ideal surface passivation. For identical conditions, Voc attains a lower value of 750 mV for a 180-μm-thick substrate. The dependence of Voc on bandgap of tunnel layers has also been observed by considering other materials like Si
₃
N
₄
and SiC. These results from the analytical model have been compared with results from a simulation using automat FOR simulation of HETerostructures v2.5 and have been found to be in good agreement with each other.