Doping of silicon nanowires by ion implantation and flash lamp annealing

In this work, we report on non-equilibrium processing for controlled doping of Si/SiO2 core/shell nanowires with shallow- and deep-level dopants below and above their equilibrium solid solubility. In detail, the shallow-level dopants B and P as well as the deep-level dopant Se was implanted, followed by millisecond flash lamp annealing. In case of amorphization upon high-fluence implantation, recrystallization takes place via a bottom-up template-assisted solid phase epitaxy. Non-equilibrium Se concentrations lead to the formation of an intermediate band in Si which in turn causes a room-temperature sub-band gap photoresponse of the nanowire when configured as a photoconductor device [1]. Alternatively, the formation of a cross-sectional p-n junction is demonstrated by co-implanting P and B in individual nanowires at different depth along the NW core.
[1] Y. Berencén, et al. Adv. Mater. Interfaces 2018, 1800101