A model for luminescence of localized state ensemble

TL;DR

This paper introduces a new distribution function for localized carriers and develops a model for luminescence in localized state ensembles, accurately explaining anomalous temperature behaviors and connecting to existing models.

Contribution

A novel distribution function and a comprehensive luminescence model for localized states are proposed, capturing complex temperature-dependent behaviors and unifying previous models.

Findings

Model reproduces anomalous temperature behaviors of luminescence.

Reduces to band-tail and quenching models under specific conditions.

Quantitative agreement with experimental luminescence data.

Abstract

A distribution function for localized carriers, $f(E,T)=\frac{1}{e^{(E-E_a)/k_BT}+\tau_{tr}/\tau_r}$, is proposed by solving a rate equation, in which, electrical carriers' generation, thermal escape, recapture and radiative recombination are taken into account. Based on this distribution function, a model is developed for luminescence from localized state ensemble with a Gaussian-type density of states. The model reproduces quantitatively all the anomalous temperature behaviors of localized state luminescence. It reduces to the well-known band-tail and luminescence quenching models under certain approximations.