Excitation of the porous silicon photoluminescence by a multiphoton vibronic process

Abstract

We study the emission of photons from porous Si after high-level vibrational excitation in the Si-O absorption band using a pulsed CO2 laser. Narrow resonances in the efficiency of light generation are discovered at 1030 cm-~ and 1084 cm-i. For excitation at 1030 cm-m the familiar photoluminescence band of porous Si appears. Time-resolved pump-to-probe experiments show the same decay times for the photo and the IR-induced luminescence. We suggest a microscopic process responsible for the light emission.

Photoluminescent 1–2 nm Sized Silicon Nanoparticles: A Surface-Dependent System

“…Moreover, since no correlation between the quenching rate and the particle surface chemistry is observed, it is expected that the silicon structure is involved in leading to dark (nonemitting) clusters. These observations are in agreement with those by Diener and co-workers indicating that IR excitation of porous silicon results in a drop in the PL intensity but only with a slight change in the PL lifetime. The authors suggested that IR excitation creates additional dangling bonds or opens additional nonradiative channels leading to an increase of the fraction number of dark crystallites.…”