The impact of single donor and donor-acceptor pair on electronic and transport properties of silicon nanostructures

We present first-principles calculations of electronic and transport properties of silicon (Si) nanorods with sizes smaller than the Bohr radius, doped with single phosphorus (P) or co-doped with P and B (boron). For P-doped nanorods, we found that the first conductive energy state (1^st CS) remains nearly unchanged by reducing the nanorod size, resulting in an electron binding energy (E_b) practically independent on size. This is due to the counterbalance between quantum confinement and attractive interaction from the P donor. We show, however, that E_b depends on the P position in Si cross-shaped nanostructures. Finally, the impact of P-B interaction on electronic and transport properties of Si nanostructures is investigated.