Barrier inhomogeneities of Al/p-In2Te3 thin film Schottky diodes

The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of p-In2Te3/Al thin films Schottky diodes papered by Flash Evaporation technique were measured in the temperature range 303-335 K have been interpreted on the basis of the assumption of a Gaussian distribution of barrier heights (φbo) due to barrier height inhomogeneities that prevail at the interface. It has been found that the occurrence of Gaussian distribution of BHs is responsible for the decrease of the apparent BH (φbo) and increase of the ideality factor (η). The inhomogeneities are considered to have a Gaussian distribution with a mean barrier height of (φbm) and standard deviation (σs) at zero-bias. Furthermore, the activation energy value (φb) at T = 0 and Richardson constant (A**) value was obtained as 0.587 eV and 3.09 Acm– 2 K– 1 by means of usual Richardson plots. Hence, it has been concluded that the temperature dependence of the I-V characteristics of p-In2Te3/Al Schottky Diodes can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the BHs. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

Mechanochemically Synthesized CIGS Nanocrystalline Powder for Solar Cell Application

Copper Indium Gallium Diselenide (CIGS) is a compound semiconductor material from the group of I-III-VI. The material is a solid solution of copper, indium and selenium (CIS) and copper, gallium and selenium with an empirical formula of CuIn(1 – x)GaxSe2, where 0 x 1. CIGS has an exceptionally high absorption coefficient of more than 105 cm – 1 for 1.5 eV. Solar cells prepared from absorber layers of CIGS materials have shown an efficiency higher than 20 %. CuIn(1 – x)GaxSe2 (x 0.3) nanocrystalline compound was mechanochemically synthesized by high-energy milling in a planetary ball mill. The phase identification and crystallite size of milled powders at different time intervals were carried out by X-ray diffraction (XRD). The XRD analysis indicates chalcopyrite structure and the crystallite size of about 10 nm of high-energy milled CIGS powder after two and half hours of milling. An attempt for preparing the thin film from CIGS nanocrystalline powder was carried out using the flash evaporation technique. Scanning electron microscopy (SEM) reveals uniform distribution of CIGS particles in thin film. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Mechanochemically Synthesized CIGS Nanocrystalline Powder for Solar Cell Application

Copper Indium Gallium Diselenide (CIGS) is a compound semiconductor material from the group of I-III-VI. The material is a solid solution of copper, indium and selenium (CIS) and copper, gallium and selenium with an empirical formula of CuIn(1 – x)GaxSe2, where 0 x 1. CIGS has an exceptionally high absorption coefficient of more than 105 cm – 1 for 1.5 eV. Solar cells prepared from absorber layers of CIGS materials have shown an efficiency higher than 20 %. CuIn(1 – x)GaxSe2 (x 0.3) nanocrystalline compound was mechanochemically synthesized by high-energy milling in a planetary ball mill. The phase identification and crystallite size of milled powders at different time intervals were carried out by X-ray diffraction (XRD). The XRD analysis indicates chalcopyrite structure and the crystallite size of about 10 nm of high-energy milled CIGS powder after two and half hours of milling. An attempt for preparing the thin film from CIGS nanocrystalline powder was carried out using the flash evaporation technique. Scanning electron microscopy (SEM) reveals uniform distribution of CIGS particles in thin film. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Structure and substructure properties of magnesium oxide thin films

In this paper we have conducted a comprehensive study of the structural and substructural characteristics of magnesium oxide films by X-ray diffraction analysis. Thin films of MgO were prepared by spray pyrolysis technique from a magnesium chloride solution. Identified the phase composition, the lattice constant, crystallite size and coherent scattering domain size, microstrain level of the films. The optimal conditions for the application of homogeneous single-phase films of stoichiometric composition were identified.This research was supported by the Ministry of Education and Science of Ukraine (Grant No. 0113U000131, No. 0112U000772) and also thankful to UGC for providing a financial assistance to the department under DRS [file no. 530/16/DRS/2013(SAP-1)]

Thickness-dependent Electrochromic Properties of Amorphous Tungsten Trioxide Thin Films

Tungsten Trioxide (WO3) thin films were grown by thermal evaporation method to study the effect of film’s thickness on its electrochromic (EC) properties. The WO3 thin films of different thicknesses were grown on Indium Tin Oxide (ITO) coated glass and soda lime (bare) glass substrate held at room temperature. The surface composition of the thin films was investigated using X-ray photoelectron spectroscopy measurement, which showed the oxygen to tungsten atomic composition ratio to be nearly 2.97. The EC properties of the thin films were examined using electrochemical techniques. Cyclic-voltammetery shows the diffusion coefficient (D) of the intercalated H+ ion in the WO3 thin film increases with the film’s thickness. It turns out that the ‘thicker’ film exhibits better coloration efficiency (CE) as compared to the ‘thinner’ film. The coloration time was found to be independent of film thickness; however, the bleaching time increases as the film thickness increases

Thickness-dependent electrochromic properties of amorphous tungsten trioxide thin films

Tungsten Trioxide (WO3) thin films were grown by thermal evaporation method to study the effect of film’s thickness on its electrochromic (EC) properties. The WO3thin films of different thicknesses were grown on Indium Tin Oxide (ITO) coated glass and soda lime (bare) glass substrate held at room temperature. The surface composition of the thin films was investigated using X-ray photoelectron spectroscopy measurement, which showed the oxygen to tungsten atomic composition ratio to be nearly 2.97. The EC properties of the thin films were examined using electrochemical techniques. Cyclic-voltammetery shows the diffusion coefficient (D) of the intercalated H+ ion in the WO3 thin film increases with the film’s thickness. It turns out that the ‘thicker’ film exhibits better coloration efficiency (CE) as compared to the ‘thinner’ film. The coloration time was found to be independent of film thickness; however, the bleaching time increases as the film thickness increases

Thickness-dependent electrochromic properties of amorphous tungsten trioxide thin films

Tungsten Trioxide (WO3) thin films were grown by thermal evaporation method to study the effect of film’s thickness on its electrochromic (EC) properties. The WO3thin films of different thicknesses were grown on Indium Tin Oxide (ITO) coated glass and soda lime (bare) glass substrate held at room temperature. The surface composition of the thin films was investigated using X-ray photoelectron spectroscopy measurement, which showed the oxygen to tungsten atomic composition ratio to be nearly 2.97. The EC properties of the thin films were examined using electrochemical techniques. Cyclic-voltammetery shows the diffusion coefficient (D) of the intercalated H+ ion in the WO3 thin film increases with the film’s thickness. It turns out that the ‘thicker’ film exhibits better coloration efficiency (CE) as compared to the ‘thinner’ film. The coloration time was found to be independent of film thickness; however, the bleaching time increases as the film thickness increases

Structure and substructure properties of magnesium oxide thin films

In this paper we have conducted a comprehensive study of the structural and substructural characteristics of magnesium oxide films by X-ray diffraction analysis. Thin films of MgO were prepared by spray pyrolysis technique from a magnesium chloride solution. Identified the phase composition, the lattice constant, crystallite size and coherent scattering domain size, microstrain level of the films. The optimal conditions for the application of homogeneous single-phase films of stoichiometric composition were identified.This research was supported by the Ministry of Education and Science of Ukraine (Grant No. 0113U000131, No. 0112U000772) and also thankful to UGC for providing a financial assistance to the department under DRS [file no. 530/16/DRS/2013(SAP-1)]

DES13S2cmm: the first superluminous supernova from the Dark Energy Survey

We present DES13S2cmm, the first spectroscopically-confirmed superluminous supernova (SLSN) from the Dark Energy Survey (DES). We briefly discuss the data and search algorithm used to find this event in the first year of DES operations, and outline the spectroscopic data obtained from the European Southern Observatory (ESO) Very Large Telescope to confirm its redshift (z = 0.663 +/- 0.001 based on the host-galaxy emission lines) and likely spectral type (type I). Using this redshift, we find M_U_peak = -21.05 +0.10 -0.09 for the peak, rest-frame U-band absolute magnitude, and find DES13S2cmm to be located in a faint, low metallicity (sub-solar), low stellar-mass host galaxy (log(M/M_sun) = 9.3 +/- 0.3); consistent with what is seen for other SLSNe-I. We compare the bolometric light curve of DES13S2cmm to fourteen similarly well-observed SLSNe-I in the literature and find it possesses one of the slowest declining tails (beyond +30 days rest frame past peak), and is the faintest at peak. Moreover, we find the bolometric light curves of all SLSNe-I studied herein possess a dispersion of only 0.2-0.3 magnitudes between +25 and +30 days after peak (rest frame) depending on redshift range studied; this could be important for 'standardising' such supernovae, as is done with the more common type Ia. We fit the bolometric light curve of DES13S2cmm with two competing models for SLSNe-I - the radioactive decay of 56Ni, and a magnetar - and find that while the magnetar is formally a better fit, neither model provides a compelling match to the data. Although we are unable to conclusively differentiate between these two physical models for this particular SLSN-I, further DES observations of more SLSNe-I should break this degeneracy, especially if the light curves of SLSNe-I can be observed beyond 100 days in the rest frame of the supernova.Comment: Accepted by MNRAS (2015 January 23), 13 pages, 6 figures, 2 table

First cosmology results using SNe Ia from the dark energy survey: analysis, systematic uncertainties, and validation

International audienceWe present the analysis underpinning the measurement of cosmological parameters from 207 spectroscopically classified type Ia supernovae (SNe Ia) from the first three years of the Dark Energy Survey Supernova Program (DES-SN), spanning a redshift range of 0.01