Electronic structure and light-induced conductivity in a transparent refractory oxide

TL;DR

This study combines theoretical and experimental methods to uncover how hydrogen annealing and UV-irradiation drastically increase conductivity in a transparent oxide through electron hopping mechanisms, offering insights for material enhancement.

Contribution

It identifies the atomic pathways and mechanisms of light-induced conductivity changes in 12CaO.7Al2O3, and proposes doping strategies to further enhance its electrical properties.

Findings

Conductivity increases by 10 orders of magnitude after treatment.

Electron hopping is the primary charge transport mechanism.

Specific doping can further improve conductivity.

Abstract

Combined first-principles and experimental investigations reveal the underlying mechanism responsible for a drastic change of the conductivity (by 10 orders of magnitude) following hydrogen annealing and UV-irradiation in a transparent oxide, 12CaO.7Al2O3, found by Hayashi et al. The charge transport associated with photo-excitation of an electron from H, occurs by electron hopping. We identify the atoms participating in the hops, determine the exact paths for the carrier migration, estimate the temperature behavior of the hopping transport and predict a way to enhance the conductivity by specific doping.