Electron microscopy and diffraction studies of pulsed laser deposited cuprous oxide thin films grown at low substrate temperatures

Autor: David Cherns, Richard F. Webster, Syed Farid Uddin Farhad
Rok vydání: 2018
Předmět:
Zdroj: Materialia. 3:230-238
ISSN: 2589-1529
Popis: Nanocrystalline Cu2O thin films have been grown on air cleaved NaCl(100) substrates at relatively low temperatures (25 °C ≤ Tsub ≤ 300 °C) by Pulsed Laser Deposition. Structural analysis by Transmission Electron Microscopy(TEM) revealed that films grown at 25 °C ≤ Tsub ≤ 200 °C with O2pp ≈ 3–5 mTorr and Laser pulse energy ≈ 25 mJ are single phase and partially epitaxial with {001}Cu2O|| {001}NaCl and Cu2O || NaCl epitaxy. A distinct metastable phase, CuxOy, was found to predominate at higher substrate temperatures up to 300 °C. Selected area electron diffraction (SAED) patterns in TEM revealed that CuxOy has a cubic structure based on Cu2O but with a lattice parameter that is ∼1.5–3% greater than that of pure Cu2O. The evidence for CuxOy as a defect variant of a basic Cu2O structure is further reinforced by Raman and Photoluminescence analyses and copper vacancy related defects in the basic cuprite cell are attributed to lead the lattice parameter expansion compared to pure Cu2O.
Databáze: OpenAIRE