Co-dopants induced tunnel-current enhancement and their interaction in silicon nano tunnel diode

We report for ultra-thin Si tunnelling diodes that negative differential conductance (NDC) is dominated by the excess current at room temperature. This is attributed to the gap-states induced by the co-dopants in the pn junction. First-principles simulation shows that the presence of co-dopants in the pn junction region leads to an increase in the interband tunnelling current by two orders of magnitude. Furthermore co-dopants interaction plays a key role in the interband tunnelling. In the absence of dopants states in the pn junction region, raising the doping concentration at source region does not give an appreciable improvement in tunnelling current.