13 research outputs found
Preparation of Zinc-Sulfide Thin Films in the Presence of Sodium Tartrate as a complexing agent
The article offers information on the experiment done for the electrodeposition of zinc-sulfide (ZnS) thin films on the titanium substrate in the presence of sodium tartrate as a complexing agent. It states that the electrodeposition process has several advantages such as the possibility for large-scale production and minimum waste of components. It mentions that depositions were carried out by varying the deposition potential to determine the optimal conditions of deposition of ZnS thin film
Secondary crystalline phases identification in Cu2ZnSnSe4 thin films: contributions from Raman scattering and photoluminescence
In this work, we present the Raman peak
positions of the quaternary pure selenide compound
Cu2ZnSnSe4 (CZTSe) and related secondary phases that
were grown and studied under the same conditions. A vast
discussion about the position of the X-ray diffraction
(XRD) reflections of these compounds is presented. It is
known that by using XRD only, CZTSe can be identified
but nothing can be said about the presence of some secondary
phases. Thin films of CZTSe, Cu2SnSe3, ZnSe,
SnSe, SnSe2, MoSe2 and a-Se were grown, which allowed
their investigation by Raman spectroscopy (RS). Here we
present all the Raman spectra of these phases and discuss
the similarities with the spectra of CZTSe. The effective
analysis depth for the common back-scattering geometry
commonly used in RS measurements, as well as the laser penetration depth for photoluminescence (PL) were estimated
for different wavelength values. The observed
asymmetric PL band on a CZTSe film is compatible with
the presence of CZTSe single-phase and is discussed in the
scope of the fluctuating potentials’ model. The estimated
bandgap energy is close to the values obtained from
absorption measurements. In general, the phase identification
of CZTSe benefits from the contributions of RS and
PL along with the XRD discussion.info:eu-repo/semantics/publishedVersio
Effect of exposure to electron beam irradiation in biopolymer papain and their electrical behaviour
33-38The obtention of
biopolymer papain irradiated with 8 MeV energy of electron beam to different
doses from 1 kGy to
10 kGy and the effect of the radiation on the electrical behaviour of the
biopolymer have been investigated in the temperature range 29°-135<span style="font-family:Symbol;mso-ascii-font-family:
" times="" new="" roman";mso-hansi-font-family:"times="" roman";mso-char-type:symbol;="" mso-symbol-font-family:symbol"="" lang="EN-GB">°C. The <i style="mso-bidi-font-style:
normal">ac impedance plots indicate a single relaxation process in
biopolymer papain in different temperatures. An increase in bulk electrical
conductivity was noted for biopolymer papain with temperature after irradiation
which is related to the hopping of charge carriers between the sites. The
electrical conductivity of fresh and irradiated papain follows the universal
power law and from which it is observed that the <i style="mso-bidi-font-style:
normal">ac conductivity is frequency dependent and it obeys the electron
tunneling model of conduction mechanism. The SEM images reveal the larger
particle size with non-uniform structure upon irradiation of papain.
</span
Enhancement in threshold voltage with thickness in memory switch fabricated using GeSe1.5S0.5 thin films
Investigations on the electrical switching, structural, optical and photoacoustic analysis have been undertaken on chalcogenide GeSe1.5S0.5 thin films of various thicknesses prepared by vacuum evaporation technique. The decrease of band gap energy with increase in film thickness has been explained using the `density of states model'. The structural units of the films are characterized using Raman spectroscopy and the deconvoluted Raman peaks obtained from Gaussian fit around 188 cm(-1), 204 cm(-1) and 214 cm(-1) favors Ge-chalcogen tetrahedral units forming corner and edge sharing tetrahedra. All the thin films samples have been exhibited memory-type electrical switching behavior. An enhancement in the threshold voltages of GeSe1.5S0.5 thin films have been observed with increase in film thickness. The thickness dependence of switching voltages provide an insight into the switching mechanism and it is explained by the Joule heating effect. (C) 2014 Elsevier B.V. All rights reserved