Quantum confinement effect on defect level of hydrogen doped rutile VO2 nanowires

Abstract

Accurate description of solubility and defect ionization energies in low dimensional nanostructures is critical for electronic applications of semiconductors with improved functionalities. Here, we present quantum confinement effect driven strategies for tuning defect level of hydrogen doping in the core region of rutile VO2(R) nanowires. The inverse dependence of a bandgap with a diameter (∝d−0.48) confirms the presence of quantum confinement effect in nanowires. The hydrogen doping in both interstitial and substitution at the O site behaves as a deep donor in low diameter nanowires, where the effect of quantum confinement is significant. The position of a donor charge transition level becomes increasingly shallower with increased nanowire diameters. The ionization energies of hydrogen defects decrease for larger-diameter nanowires due to the dielectric screening effect increment. This indicates the possibility of achieving n-type dopability with large diameter VO2(R) nanowires. This study prescribes the strategies for optimizing doping and the defect level for extensive applications of highly correlated 1D nanostructured materials.