Phosphorus Doping of Si Nanosheets by Spin-on Dopant Proximity

Low-dimensional silicon (Si) nanostructures have been attracting a significant attention for various applications including electrical, optical, energy devices, and bio-chemical sensors. Two-dimensional Si nanostructures, i.e., Si nanosheets (SiNSs), are promising owing to their extremely large surface area, mechanical flexibility, and band gap modulation. In order to exploit the potentials of SiNSs, the doping of these nanostructures is crucial; however, this has not been yet extensively investigated. In this paper, we report an n-type phosphorus doping of SiNSs using a spin-on dopant proximity technique that was employed to deposit a thin film of phosphosilicate glass by evaporation. Structural and X-ray measurements results reveal that the phosphorus atoms are substitutionally doped and that the crystallinity and structure of the SiNSs are preserved after the doping. Electrical measurements show that the SiNSs are heavily n-type doped. The doping level can be modulated by adjusting the annealing temperature.