PL (left axis) and absorption (right axis) spectra of a typical sample (, , ). The dashed line is a result of fitting by assuming an indirect bandgap semiconductor . The optical bandgap is estimated to be 2.4 eV.
Results of -scan measurements for (a) a closed aperture , (b) an open aperture , and (c) the ratio of the two results . The squares are experimental results and the solid curves are results of fittings.
(left axis) and (right axis) spectra of a typical sample (, , ). The dashed and dotted curves are PL and absorption spectra, respectively.
spectra of samples with different excess Si concentrations and different annealing temperatures . The same colored (or shaped) symbols are used for the same (or ) samples.
Si concentration dependence of . The inset shows the size dependence of the microscopic nonlinear refractive index of Si-ncs. The dotted line is a dependence predicted by a simple quantum confinement model.
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