Effect of oxygen partial pressure on the photoluminescence properties of sol–gel synthesized nano-structured ZnO thin films

• Published in: Thin solid films Vol. 550; pp. 65 - 70
• Main Authors: Das, Sagnik, Bhattacharjee, Kaustav, Maitra, Saikat, Das, G.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diffraction patterns; Exact sciences and technology; Heat treatment; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other topics in nanoscale materials and structures; Partial pressure; Photoluminescence; Physics; Reducing atmospheres; Scanning electron microscopy; Sol–gel; Spin coating; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Zinc oxide; Nanoparticles; Zinc oxide; Sol–gel; Spin coating; Photoluminescence; Defect states; Temperature dependence; Particle size; Sol-gel; XRD; SAED; Nanostructures; Electron microscopy; Precursor; Heat treatments; Thin films; Diffraction pattern analysis; Transmission electron microscopy; Partial pressure; Spin-on coatings; Spin-on coating; Particle size measurement; Scanning transmission electron microscopy; Nanostructured materials; Sol-gel process
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.10.045

Nanostructured ZnO thin films were prepared by spin coating on glass substrate. The precursor ZnO gel powder was thoroughly characterized by particle size measurement, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and selected area diffraction pattern analyses. The sol on heating at 450–650°C resulted in the formation of dried mass with particle size in the range of 30–40nm. The photoluminescence (PL) peak of ZnO thin film heat treated at 450°C for different periods appeared at 400nm. But when the film was heat treated at the same temperature (450°C) under reducing atmosphere, another PL peak appeared at 443nm. Heat treatment of the film at 650°C for 3h under reducing atmosphere resulted in the appearance of PL peaks at 500 and 555nm. The PL peaks developed were related to the defect states of zinc oxide lattice developed at different oxygen partial pressures during the heat treatment. •Nano-structured ZnO thin films were prepared by spin coating.•Heat treatment at different conditions generates different defect states in ZnO.•The defect states control photoluminescence of ZnO at 400, 443, 500 and 555nm.