Improvement in short circuit current of p-i-n solar cell with silicon quantum dot superlattice structure by optimizing SiNx thickness

Superlattice consisting of 10 alternate layers of a-Si with QDs and SiN
_x
are incorporated as i-layer in a p-i-n solar cell using HWCVD method. Superlattice with QDs showed absorption coefficient in the range of ~10
⁵
-10
⁴
cm
^-1
. Calculated optical bandgap of the SL with QDs (~1.84 eV) is higher than the SL without QDs (~1.79 eV) and this is attributed to QCE. The cells with QDs showed I
_SC
= 1.806 μA and V
_OC
= 25 mV. Increase in I
_SC
of cells is attributed to increase in tunneling current due to decrease in SiN
_x
thickness. Low V
_OC
has been attributed to the thin SiN
_x
layers, the defects and the interface states which result in recombination.