The Transiently Unstable Phenomenon of I–V Curves of ITO/a-Si:H Junctions

The current–voltage measurement, or I–V curve, is one of the primary methods used to investigate the electrical, photoelectric/photovoltaic, and applicability properties of the semiconductor/semiconductor, metal/semiconductor, and electrical junctions in general, and highlighting indium tin oxide (ITO)/hydrogenated amorphous silicon (a-Si:H) junctions in particular. In this study, we focus on a phenomenon not previously reported by any researcher: the transient instability observed in I–V curves during initial measurement cycles. We propose that this instability may be caused by weak bonds between silicon (Si) and hydrogen (H) ions. Specifically, H⁺ ions located beyond the depletion region within the a-Si:H layer may jump between neighboring Si ions and move within the a-Si:H layer in response to the voltage applied during I–V measurements. Our studies demonstrate that limiting the number of H⁺ ions beyond the depletion region through adjustments to the thickness and the doping concentration of the a-Si:H layer mitigates this instability immediately after fabricating ITO/a-Si:H junctions.