Exciton localization in doped Si nanocrystals from single dot spectroscopy studies

Abstract

The results of low-temperature photoluminescence characterization of single silicon nanocrystals prepared from highly doped silicon-on-insulator wafers are presented. The effect of B, P, As, and Sb impurities on ensemble as well as individual emission spectra are determined by comparison with the line shapes of undoped nanocrystals. From the statistical analysis of the luminescence spectra, the donor ionization energies for nanocrystals emitting in the range of 1.5-2.0 eV are estimated to be 140-200 meV, while the exciton-impurity binding energy for Asand Sb-doped nanocrystals is found to be about 40-45 meV.

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

“…[ 29 ] and [ 52 ] for details). Following the calculations therein, we can estimate the P-ionization energy of the J -peak (or respectively the beginning of the J -plateau) to ≈200 meV, in accordance with literature values on ionization energies of nano-sized Si [ 54 – 55 ]. For SRO:P the J -plateau indicates a broader distribution of P-ionization energies towards even larger values.…”

Structure of whispering gallery mode spectrum of microspheres coated with fluorescent silicon quantum dots

“…There is one previous report of SD in Si QDs, in which the single-particle linewidth narrowed from 150 to 105 meV when the collection time was shortened by a factor of 100, at room temperature [34]. More recent reports have shown that individual luminescence spectra of Si-QDs can jump over a range of about 100 meV [40,41]. Thus spectral diffusion could play an important role in the observed fluorescence WGM spectra.…”

Scaling size of the interplay between quantum confinement and surface related effects in nanostructured silicon

“…[2][3][4][5][6][7] Considering the dimensions of the nanostructures, the measured data allow the precise determination of the interplay between QC and surface related effects and represent an important starting point for the investigation of this interplay in the general case of semiconductor nanostructures. Finally, the reported exemplar study delineates the capability to use the band alignment evolution as a robust approach to experimental investigate how the different configurations (such as the semiconductor material, 28 shape, 29,30 strain, 26,31 or doping; 32,33 the host matrix material 34,35 or density; 26 and the system dimensionality 36 ) affect the properties of the nanostructured interfaces.…”