Quantum Confinement Effects and Electronic Properties of SnO2 Quantum Wires and Dots

Abstract

On the basis of the density functional theory (DFT) within local density approximations (LDA) approach, we calculate the band gaps for different size SnO2 quantum wires (QWs) and quantum dots (QDs). A model is proposed to passivate the surface atoms of SnO2 QWs and QDs. We find that the band gap increases between QWs and bulk evolve as ΔEgwire = 1.74/d1.20 as the effective diameter d decreases, while being ΔEgdot = 2.84/d1.26 for the QDs. Though the ∼d1.2 scale is significantly different from ∼d2 of the effective mass result, the ratio of band gap increases between SnO2 QWs and QDs is 0.609, very close to the effective mass prediction. We also confirm, although the LDA calculations underestimate the band gap, that they give the trend of band gap shift as much as that obtained by the hybrid functional (PBE0) with a rational mixing of 25% Fock exchange and 75% of the conventional Perdew−Burke−Ernzerhof (PBE) exchange functional for the SnO2 QWs and QDs. The relative deviation of the LDA calculated band gap ...