Heterojunction solar cell with titanium dioxide nanolayer with an efficiency of 10.1%

We present a solar cell based on a titanium dioxide / p-type silicon charge carrier separating heterojunction with an efficiency of 10.1%, on a cell area of 0.9 cm
²
. The solar cells were fabricated using industrial feasible processes like laser fired contacts on the rear and silicon nitride antireflection coating on the front side. The ultra-thin TiO
₂
layers (2.5 to 5.0 nm) were deposited on p-type Si wafers by means of Atomic Layer Deposition (ALD), using Tetrakis-dimethyl-amido-titanium (TDMAT) and water at a process temperature of 150°C. A current density of 35 mA/cm
²
was achieved with 2.5 nm TiO
₂
. By means of Suns-F
_oc
measurements, the loss in fill factor was identified to be due to the high series resistance. Using the series resistance free pseudo fill factor the current solar cell design achieves a pseudo efficiency of 13.4%.