Ballistic effect in red photoluminescence of Si wires

Abstract

The excitation, emission, electron paramagnetic resonance, and Raman scattering spectra of as-prepared and aged Si wires, like porous silicon, have been examined. Atomic force microscope is used for the surface morphology investigation, as well as the study of this morphology connection with photoluminescence (PL) peculiarities. Two elementary PL bands in red and orange spectral ranges: $h{\ensuremath{\nu}}_{m}=1.70--1.73$ and 1.80--2.00 eV, have been observed. It is shown the ballistic effect can enhance very effective hot carrier excitation of interface-defect related PL $(h{\ensuremath{\nu}}_{m}=1.70--1.73 \mathrm{eV})$ in low-dimensional Si wire structures. The confirmation of the last conclusion is important for understanding the mechanism of Si wire PL and successful application of Si low-dimensional structures in optoelectronics devices.