Tunneling Contributions to NiP and Pin Hydrogenated Amorphous Silicon Devices

Abstract

It is well known that the performance of hydrogenated amorphous silicon (a-Si) p-i-n type devices is determined by the sequence of deposition. For instance, the stainless steel/p-i-n configuration generally shows a larger value of the open circuit voltage (up to 200mV) compared to the n-i-p sequence of deposition \1,2]. Explanations of this phenomena such as the Dember potential \1], self field effect \2], residual doping \3], hydrogen effusion effects associated with the p+ layer deposition process \4, 5] are unable to satisfactorily explain the difference in performance.

Temperature Dependence of a-Si:H Nip Diodes

“…Under illumination, drift/diffusion and recombination processes were related to the open circuit voltage of solar cell diodes with recombination limiting the open circuit voltage of diodes with high built-in potential (7). Tunnelling at the p/i interface has also been considered, particularly as a mechanism limiting the open circuit voltage (8,9). The exact nature of the tunnelling process is unclear, with some papers speculating that hole (9) and others that electron (8, 10) tunnelling takes place.…”