Nanoscale Characterization of Active Doping Concentration in Boron-Doped Individual Si Nanocrystals

摘要

Doping of Si nanocrystals (NCs) is essential to the photonic and photovoltaicapplications. In this work, individual Si NCs on Si substrate are prepared byexcimer laser crystallization technique. The doping effect of boron (B) atomsis characterized at the nanoscale by Kelvin probe force microscopy (KPFM)measurement. The KPFM signal of B-doped Si NCs is found opposite to thatof intrinsic counterparts, indicating that active B doping is obtained.Moreover, the surface potential is reconstructed from KPFM images byGreen’s electrostatic theorem and deconvolution processing, and accordinglythe active doping concentration is calculated around 10~(17)–10~(18) cm~(-3). Thedoping efficiency is then estimated less than 1% and the possible reason isdiscussed.