Electronic Structures of Oxygen-deficient Ta2O5

TL;DR

This paper uses first-principles calculations to analyze the electronic structures of crystalline and oxygen-deficient Ta2O5, revealing stable vacancy configurations and their impact on electronic properties relevant to devices.

Contribution

It provides the first detailed computational study of oxygen vacancies in Ta2O5, identifying stable structures and their electronic effects, which differ from previous models.

Findings

Stable oxygen vacancy configurations identified

Vacancy-induced shallow levels near conduction band

Implications for leakage current in electronic devices

Abstract

We provide a first-principles description of the crystalline and oxygen-deficient Ta2O5 using refined computational methods and models. By performing calculations on a number of candidate structures, we determined the low-temperature phase and several stable oxygen vacancy configurations, which are notably different from the previous results. The most stable charge-neutral vacancy site induces a shallow level near the bottom of conduction band. Stability of different charge states is studied. Based on the results, we discuss the implications of the level structures on experiments, including the leakage current in Ta2O5-based electronic devices and catalysts.