Simulation and fabrication of a-Si:H thin-film solar cells: a comparative study of simulation and experimental results

Both simulation and experimental studies on single-junction hydrogenated amorphous silicon (a-Si:H) thin-film solar cells are done. Hydrogenated amorphous silicon (a-Si:H) thin-film solar cells with n-i-p structure are simulated using AFORS-HET (Automated For Simulation of Heterostructure) software and fabricated using radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) (13.56 MHz) multi-chamber system at a low temperature of 180 °C. The effect of emitter layer (a-Si:H (p)) doping and absorber layer (a-Si:H (i)) thickness is studied. Further, simulation results are compared with the experimental results. To map the diborane (B₂H₆) flow rate in the experiment to corresponding doping concentration in simulation, the diborane (B₂H₆) flow rate is varied from 8 to 14 sccm, and emitter layer doping from 7.2 \(\times\) $\times$ 10¹⁹ to 8.4 \(\times\) $\times$ 10¹⁹ cm⁻³. It is observed that solar cell parameters \({J}_{sc}\) $J_{\mathit{sc}}$ , \({V}_{oc}\) $V_{\mathit{oc}}$ corresponding the doping concentration 7.6 \(\times\) $\times$ 10¹⁹ cm⁻³ in simulation matches quite well when diborane (B₂H₆) flow rate is 10 sccm in the experiment. The solar cell’s efficiency is also found to be within error bars with values of 5.79% for simulation and 5.50% for experiment. Using these doping concentrations and B₂H₆ flow rate subsequently, the absorber layer thickness is varied from 200 to 350 nm to further optimize the device thickness to improve the efficiency. The simulation results indicate that increasing the thickness leads to improved \({J}_{sc}\) $J_{\mathit{sc}}$ and overall performance of the solar cell. A similar trend is observed from the experimentally fabricated devices with the same variation, which shows a good match between simulation and experiment.