Size-dependent optical and dielectric properties of nanocrystalline ZnS thin films synthesized via rf-magnetron sputtering technique

Journal Article · Thu Mar 22 00:00:00 EDT 2007 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2006.06.019· OSTI ID:21000606

Ghosh, P K ^[1]; Jana, S ^[1]; Nandy, S ^[1]; Chattopadhyay, K K ^[1]

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1. Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700 032 (India)

Nanocrystalline ZnS thin films have been synthesized by radio frequency magnetron sputtering technique on glass and Si substrates at a substrate temperature 300 K. X-ray diffraction and selected area electron diffraction studies confirmed the formation of nanocrystalline cubic phase of ZnS in the films, although the target material was hexagonal ZnS. The particle size, calculated from the XRD patterns of the thin films was found in the range 2.06-4.86 nm. TEM micrographs of the thin films revealed the manifestation of ZnS nanoparticles with sizes in the range 3.00-5.83 nm. UV-vis-NIR spectrophotometric measurements showed that the films were highly transparent ({approx}90%) in the wavelength range 400-2600 nm with a blue shift of the absorption edge. The direct allowed bandgaps have been calculated and they lie in the range 3.89-4.44 eV. The particle size, calculated from the shift of direct bandgap, due to quantum confinement effect lying in the range 3.23-5.60 nm, well support the TEM results. The room temperature photoluminescence spectra of the films showed two peaks centered around 315 and 450 nm. We assigned the first peak due to bandgap transitions while the latter was due to sulfur vacancy in the films. The composition analysis by energy dispersive X-rays also supported the existence of sulfur deficiency in the films. The dielectric property study showed high dielectric constant (85-100) at a higher frequency (>5 kHz)

• OSTI ID: 21000606
• Journal Information: Materials Research Bulletin, Vol. 42, Issue 3; Other Information: DOI: 10.1016/j.materresbull.2006.06.019; PII: S0025-5408(06)00261-3; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALS
ELECTRON DIFFRACTION
GLASS
MAGNETRONS
NANOSTRUCTURES
PARTICLE SIZE
PERMITTIVITY
PHOTOLUMINESCENCE
RADIOWAVE RADIATION
SEMICONDUCTOR MATERIALS
SPECTROPHOTOMETRY
SPUTTERING
SUBSTRATES
SULFUR
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
VACANCIES
X-RAY DIFFRACTION
ZINC SULFIDES