Electroluminescence of silicon nanocrystallites prepared by pulsed laser ablation in reduced pressure inert gas

We report on an electroluminescent (EL) diode with novel active layers of silicon (Si) nanocrystallites. The Si nanocrystallite active layer was prepared by pulsed laser ablation in an ambient of reduced pressure inert gas. The structure of the EL diodes was semitransparent platinum (Pt) electrode/Si nanocrystallite layer/p-type Si/Pt electrode. We have observed visible spectra of not only photoluminescence around 2.07 eV, but also EL around 1.66 eV at room temperature. The EL diodes showed a rectifying behavior caused by a Schottky-like junction. Furthermore, we have found that the EL diodes showed strong nonlinear dependence of EL intensity on current density. A possible mechanism of the EL diode emission is impact ionization by minority hot carriers injected through the surface oxide layers and the successive radiative recombination.