Non-toxic novel route synthesis and characterization of nanocrystalline ZnS{sub x}Se{sub 1−x} thin films with tunable band gap characteristics

Journal Article · Tue Jul 01 00:00:00 EDT 2014 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2014.04.002· OSTI ID:22348675

Shin, Seung Wook ^[1]; Vanalakar, S. A. ^[2]; Moholkar, A. V. ^[3]; Gurav, K. V.; Suryawanshi, M. P. ^[2]; Lee, Jeong Yong ^[1]

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1. Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)
2. Department of Materials Science and Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of)
3. Electrochemical Mat. Lab., Department of Physics, Shivaji University, Kolhapur 416-004 (India)

Highlights: • A simple, inexpensive, and non-toxic CBD route is used to deposit ZnS thin films. • The ZnS{sub x}Se{sub 1−x} thin films formation takes place via annealing of ZnS thin films in Se atmosphere. • S/(S + Se) ratio found to be temperature dependent and easy tuning of band gap has been done by Se atom deposition. - Abstract: An environmentally benign chemical bath deposition (CBD) route was employed to deposit zinc sulfide (ZnS) thin films. The CBD-ZnS thin films were further selenized in a furnace at various temperatures viz. 200, 300, 400, and 500 °C and the S/(S + Se) ratio was found to be dependent on the annealing temperature. The effects of S/(S + Se) ratio on the structural, compositional and optical properties of the ZnS{sub x}Se{sub 1−x} (ZnSSe) thin films were investigated. EDS analysis showed that the S/(S + Se) ratio decreased from 0.8 to 0.6 when the film annealing temperature increased from 200 to 500 °C. The field emission scanning electron microscopy and atomic force microscopy studies showed that all the films were uniform, pin hole free, smooth, and adhered well to the glass substrate. The X-ray diffraction study on the ZnSSe thin films showed the formation of the cubic phase, except for the unannealed ZnSSe thin film, which showed an amorphous phase. The X-ray photoelectron spectroscopy revealed Zn-S, Zn-Se, and insignificant Zn-OH bonds formation from the Zn 2p{sub 3/2}, S 2p, Se 3d{sub 5/2}, and O 1s atomic states, respectively. The ultraviolet–visible spectroscopy study showed ∼80% transmittance in the visible region for all the ZnSSe thin films having various absorption edges. The tuning of the band gap energy of the ZnSSe thin films was carried out by selenizing CBD-ZnS thin films, and as the S/(S + Se) ratio decreased from 0.8 to 0.6, the band gap energy decreased from 3.20 to 3.12 eV.

• OSTI ID: 22348675
• Journal Information: Materials Research Bulletin, Vol. 55; Other Information: Copyright (c) 2014 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
77 NANOSCIENCE AND NANOTECHNOLOGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
ANNEALING
ATOMIC FORCE MICROSCOPY
CRYSTALS
DEPOSITION
DEPOSITS
EV RANGE
FIELD EMISSION
NANOSTRUCTURES
OPTICAL PROPERTIES
SCANNING ELECTRON MICROSCOPY
SOLAR CELLS
SUBSTRATES
SYNTHESIS
TEMPERATURE DEPENDENCE
THIN FILMS
TOXICITY
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY
ZINC SULFIDES