TEM image of a sample prepared under the same conditions as the sample studied in this work, showing silicon nanoclusters.
(Color online) a) PL spectra as a function of pump laser power pumped at 473 nm. a) Inset: Deconvolution of spectrum taken using a pump power of 340 mW, showing two constituent emission bands. Spectra corrected for the system response. b) Peak position as a function of pump power.
(Color online) PL transients recorded using a photon counting set-up. (a) Decay; (b) rise (inverted for comparison with decay data). Solid lines are triple exponential fits.
(Color online) Fitting residuals for triple and stretched exponential fits to decay data taken at 800 nm (1.55 eV). Blue (solid line): stretched exponential; red (dotted line): triple exponential.
(Color online) Variation of the time constants of the three components of PL decay data with photon energy extracted from fits to PL data.
(Color online) Varying contributions of the three decay components to the PL signal as a function of detection energy. Red (light solid line) long component; black (heavy solid line) medium component; blue (dashed line) short component. Lines are guides for the eye.
Variation in the three lifetime components with pump power measured at an emission wavelength of 800 nm. Pump wavelength = 473 nm. a) Short component; b) medium component; c) long component.
(Color online) Comparison of the PL spectrum’s long lifetime component (data) with the transformation of the total PL spectrum, using Eq. (6) to predict the shape of the PL spectrum of luminescent acceptors (fit). Data have been normalized to aid comparison.
(Color online) PL data for the three PL decay components corrected for their relative quantum efficiencies. Red (light solid line) long component; black (dashed line) medium component; blue (heavy solid line) short component. This gives an indication of the relative populations of nanocrystals contributing to each band. Clearly, the majority of nanocrystals have a short PL decay time, and only a small minority are responsible for the long component.
(Color online) Fitting the short lifetime component PL data with two Gaussian peaks. Red (LH Gaussian peak) 1.37 eV band; blue (RH Gaussian peak) 1.52 eV band; black (bold solid line following data points) sum of two individual bands.
Chi squared results for different fits to the normalised 800 nm decay data.
Comparison of the three decay components’ relative quantum efficiencies and populations. Data measured at 800 nm with a pump power of 40 mW.
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