Variable band gap ZnO nanostructures grown by pulsed laser deposition

Abstract

ZnO band-gap was engineered for and by growing its quantum wells and nanoparticle matrices using pulsed laser deposition. Alloy thin films of Mg x Zn 1− x O grown with high crystalline quality by variable oxygen ambient pressure methodology developed by us could continuously increase the band gap up to about 3.8 eV. Increasing Cd concentration in the alloy thin films of Cd y Zn 1− y O grown with good crystalline quality monotonically decreased the band gap up to about 2.9 eV. Multilayer matrices of alumina capped ZnO nanoparticles with mean radii in the range of 1.8–3.6 nm were grown to obtain size-dependent band gap up to about 4.5 eV. These nanoparticles are understood to grow without the formation of a wetting layer on the substrate.