Trapping electrons in semiconductor air bubbles: A theoretical approach

TL;DR

This paper presents a theoretical study showing that nanometric air bubbles in semiconductor materials can trap electrons due to a self-polarization potential well caused by dielectric mismatch, with trapping strength depending on pore size.

Contribution

It introduces a theoretical model explaining electron trapping in semiconductor air bubbles via self-polarization, defining a trapping parameter for different materials.

Findings

Air bubbles can act as electron-trapping centers in semiconductors.

Trapping strength depends on pore size and material properties.

A trapping parameter helps determine maximum pore size for trapping.

Abstract

The role of image charges in nanoporous semiconductor materials is investigated within the framework of the effective mass and envelope function approximations. We show that nanometric air bubbles in these materials can act as electron-trapping centers. This trapping capability originates from a deep stabilizing self-polarization potential well induced by the air - semiconductor dielectric mismatch which can surpass the electroaffinity barrier. The trapping strength is a function of the pore size and the bulk parameters of the matrix material. A {\it trapping parameter} characteristic for each semiconductor material is defined. This parameter provides a simple way to ascertain the maximum pore size in a given material which is able to induce self-trapping of excess electrons.