Effect of carrier injection stress in thin film solar cells by impedance spectroscopy

In amorphous silicon solar cells, degradation is directly related to V _oc, FF and cell performance. The dependence of the stability of thin film amorphous silicon solar cells is studied in terms of the volume fraction of B ₂H ₆ in the p-layer. When the volume fraction of B ₂H ₆ is increased by an order of magnitude, the doping-induced defects tend to increase quite rapidly. Low-doped p-type a-SiO _x layers had better initial properties but rapidly degraded. Heavily doped p-type a-SiO _x layers had lower initial properties but displayed better stability. The improvement in stability is explained in conjunction with the capacitance and resistance values of impedance spectroscopy. When the B ₂H ₆ gas flow rate is increased, the cell is degraded showing a capacitance decay decrease from 51.75% to less than 18.18%. In addition, the increase in the resistance decreased from 90.90% to 11.73%.