Quantum confinement effects and band gap engineering of SnO2 nanocrystals in a MgO matrix

The nanocrystal formations of SnO2 in xSnO2-(100 − x)MgO (x in mol.%) nanocrystalline composite thin films lead to controllable particle size of SnO2 in MgO matrix. Under the controlled choice of composition and annealing conditions, the band gap of SnO2 can be continuously increased from 3.89 eV to 4.5 eV due to quantum confinement effect. The method provides a generic approach for tuning the band gap in nanocomposite systems over a wide range of energy.