Microstructure, local electronic structure and optical behaviour of zinc ferrite thin films on glass substrate

Abstract

Zinc ferrite thin films were deposited using a radio-frequency-sputtering method on glass substrates. As-deposited films were annealed at 200°C for 1, 3 and 5 h, respectively. X-ray diffraction studies revealed the amorphous nature of as-grown and annealed films. Thickness of as-deposited film is 96 nm as determined from Rutherford backscattering spectroscopy which remains almost invariant with annealing. Transmission electron microscopic investigations envisaged a low degree of crystalline order in as-deposited and annealed films. Thicknesses estimated from these measurements were almost 62 nm. Roughness values of these films were almost 1–2 nm as determined from atomic force microscopy. X-ray reflectivity measurements further support the results obtained from TEM and AFM. Near-edge X-ray absorption fine structure measurements envisaged 3+ and 2+ valence states of Fe and Zn ions in these films. UV–Vis spectra of these films were characterized by a sharp absorption in the UV region. All films exhibited almost the same value of optical band gap within experimental error, which is close to 2.86 eV.

UV‐Vis Spectroscopic and NEXAFS Studies of Polycrystalline Zinc Ferrite Films

“…The spectra exhibit strong absorption in UV‐region for all films. This kind of behavior is characteristics of ferrite nanoparticles and thin films . Tauc's plots were used to estimate the optical band‐gap ( E g ) for these films as where A is a constant, hν is the energy of incident radiation, t is thickness, and Abs is the absorption of film.…”

“…Film Deposition : ZnFe 2 O 4 films were grown using radio frequency (RF) sputtering method . ZnFe 2 O 4 sputtering target (99.99%) procured from Alfa‐Aesar was used for deposition.…”

“…X‐ray absorption spectroscopy (XAS) measurements for these films were performed at 10D XAS KIST beamline in PLS, operating at 3.0 GeV energy with a maximum storage current of 400 mA. The details of measuring these spectra are given elsewhere . Energy resolution ( E/ Δ E ) of the beamline is 2000–5000 with a minimal photon flux of 10 10 photons/s.…”

“…The optical response of this material is also important in the sense as it paves up the utilization of this material for photocatalytic applications . Thus, the optical behavior of zinc ferrite nanoparticles and thin films is investigated, however, the relation among local electronic structure and optical behavior still needs deeper investigations. In this context, our group has recently studied the optical behavior of zinc ferrite thin film on glass substrate using UV‐Vis spectroscopy, and estimated an optical band‐gap of 2.86 eV in these short‐ranged crystalline‐ordered films .…”

“…Thus, the optical behavior of zinc ferrite nanoparticles and thin films is investigated, however, the relation among local electronic structure and optical behavior still needs deeper investigations. In this context, our group has recently studied the optical behavior of zinc ferrite thin film on glass substrate using UV‐Vis spectroscopy, and estimated an optical band‐gap of 2.86 eV in these short‐ranged crystalline‐ordered films . This work also elaborates the local electronic structure of these films.…”