A Mechanism of Porous-Silicon Luminescence

TL;DR

This paper proposes a theoretical mechanism involving quasibound states and transition probabilities to explain the luminescence observed in porous silicon, supported by models that replicate key experimental features.

Contribution

It introduces a novel theoretical model linking mesoscopic bulges to luminescence in porous silicon, explaining spectral features and transition dynamics.

Findings

Reproduces the dominance of nonradiative transitions

Explains blue shift in finer textures

Accounts for luminescence suppression at low temperatures

Abstract

We discuss the discrete spectrum induced by bulges on threadlike mesoscopic objects, using two models, a continuous hard-wall waveguide and a discrete tight-binding model with two sorts of atomic orbitals. We show that elongated bulges induce numerous quasibound states. In the discrete model we also evaluate the probability of transition between the localized states and extended ones of the "valence" band. We suggest this as a mechanism governing the porous-silicon luminescence. In addition, the model reproduces the dominance of nonradiative transitions, blue shift for finer textures and luminescence suppression at low temperatures.