Radiative Decay Engineering of Direct Bandgap Emission in Silver Ion-Implanted Polarized Silicon Quantum Dots

Si nanocrystal (NC) in SiO2 matrix normally exhibit quasi-direct interband transitions due to band mixing of direct and indirect gaps in a nanoscale environment. Compared to direct bandgap III-V or II-VI semiconductor nano-particles, the radiative recombination coefficient of Si is rather low at room temperature B ≈ 1e-14 cc/s. Therefore, even considering the defect mediated recombination and Auger assisted non-radiative transitions to be suppressed due to spatial localization of carriers in Si nanoparticles, the electron-hole recombination lifetime is observed to be in the range of ms to microsecond. Ion implantation provides a route for synthesis of Silicon based nanocrystals for VLSI compatible nanophotonic emitters.