Title :
Analysis of Series Resistance Losses in a-Si:H/c-Si Heterojunction Solar Cells
Author :
Gogolin, Ralf ; Turcu, Mircea ; Ferre, Rafel ; Clemens, Joachim ; Harder, Nils-Peter ; Brendel, Rolf ; Schmidt, J.
Author_Institution :
Inst. for Solar Energy Res. Hamelin, Emmerthal, Germany
Abstract :
We present an experimental method to quantify the series resistance Ra-Si/ITO through the a-Si:H layers and the a-Si:H/ITO interface on test structures. In order to optimize Ra-Si/ITO, we apply different a-Si:H and ITO deposition parameters. We find the best value for R(p)-a-Si/ITO of 0.42 Ω·cm2 for an ITO double layer with a 10-nm-thin starting layer that provides good contact resistance and an additional 90-nm top layer that provides good conductivity. For R(n)-a-Si/ITO, we reach values below 0.1 Ω·cm2. We present an analysis of the series resistance and shading losses of our 100-cm2 bifacial screen-printed a-Si:H/cSi heterojunction solar cells, which show an open-circuit voltage of Voc = 733 mV, demonstrating the excellent level of interface passivation. The efficiency of 20.2% is limited by a low short-circuit current density of 37.1 mA/cm2 and fill factor of 76%.
Keywords :
amorphous semiconductors; contact resistance; current density; electrical conductivity; elemental semiconductors; hydrogen; indium compounds; passivation; semiconductor heterojunctions; short-circuit currents; silicon; solar cells; tin compounds; ITO deposition parameters; Si:H-Si-ITO; conductivity; fill factor; interface passivation; open-circuit voltage; resistance; screen-printed heterojunction solar cells; series resistance losses; short-circuit current density; Conductivity; Contact resistance; Heterojunctions; Hydrogen; Indium tin oxide; Photovoltaic cells; Resistance; Amorphous silicon; series resistance; silicon heterojunction solar cells;
Journal_Title :
Photovoltaics, IEEE Journal of
DOI :
10.1109/JPHOTOV.2014.2328575
