A Gaussian Model To Investigate The Photoluminescence Spectra Of Nanoporous Silicon Quantum Wires

The observation of visible luminescence with finite quantum efficiency at room temperaturernfrom nanoporous silicon (nP-Si) prompted renewed hope for the possiblernintegration of Silicon (Si) based light emitting devices. Since then, nP-Si quantumrnwires research has attracted considerable attention. However, the origin of photoluminescencern(PL) and the blue shift in PL peak is still a debatable issue.rnWe present a phenomenological model formulation to explain PL spectra from np-rnSi with diameters of wires ranging from 1-6 nm based on the quantum confinementrnmodel. We explicitly calculate the expression for PL spectra as a function of energyrnupshift. And we take the size distribution of nanoporous Si quantum wires as Gaussian.rnTo validate our model we compare our simulated PL spectra with experiments.rnTo observe the nature of blue shift further we use the energy gap vs. diameter as anrninput parameter from pseudopotential simulation and tight binding fit to our modelrnand generate PL that shows the same nature as experimental one. Our results clearlyrnshow the blue shift of PL as a function of energy upshift and wavelength by varyingrnthe diameter of wires. We believe that Gaussian model looking at PL of nP-Sirnquantum wires is new observation that provide very good qualitative agreement withrnother observations

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