Photoluminescence of Atomic Layer Deposition Grown ZnO Nanostructures

Abstract

Atomic Layer Deposition (ALD) technique was used to grow crystalline, nanostructured Zinc Oxide (ZnO) thin films, having very low surface roughness, on silicon (Si) and fused quartz (SiO2) substrates. The film thickness and structural properties were characterized by using X-ray reflectivity and X-ray diffraction techniques. The excitonic light emission of ZnO thin films wasstudied by means of photoluminescence (PL) measurements in the ultraviolet-visible spectral region. Characteristic near band edge emission (NBE) of the ZnO thin films corresponding to free excitonic recombination shows strong signal in the UV range at room temperature. Visible region of the PL spectra of ZnO nanostructures shows that there is no defect related deep level emission (DLE), suggesting the absence of defect states. The results confirm the growth of ZnO thin films of a high quality crystalline structure by ALD technique.