On downscaling of the tantalum oxides from three to zero dimensions

Abstract

Considering the recent interests in device miniaturization prompted by developments in nanotechnology, study of changes in physical properties of electronic materials upon downscaling to lower dimensions has become more important. This study is aimed at investigating the structural and electronic properties of the tantalum oxides (TaO, TaO2, Ta2O3, TaO3) in the bulk and lower dimensions of slab, chains and clusters. The predictions pointed out that TaO, TaO2 and Ta2O3 prefer to crystallize in bulk whereas TaO3 stabilizes in form of clusters. The bulk, slab, chains and clusters of TaO exhibit metallic character due to d-electrons at Fermi level. The bulk, slab and clusters of TaO2 offers the metallic character due to the presence of major contribution of Ta-d states at Fermi level, while the chains appeared as narrow-gap semiconductor which points to a transition from metallic to semiconducting character on downscaling. The bulk and chains of TaO3 exhibited metallic behavior due to presence of p-states on Fermi level, while the clusters are semiconductors having band gap 2.6 eV. Ta2O3 in bulk, slab and chains show metallic character due to presence of d-states of Ta at Fermi level, while the clusters possess the semiconducting nature. In general, the transition from metallic to semiconducting character is observed upon the downscaling. This study gives the valuable predictions for the future usage of these materials in several electronic applications and devices.