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Volume 5, Issue 6, (November–December  2016)

Debye-Waller Factors of Semiconductor Elements in their Compounds Studied Based on Statistical Moment Method

Original Research

Journal of Chemistry and Materials Research Vol. 5 (6), 2016, 110–114

Ha Dang Khoa, Tong Sy Tien, Nguyen Van Hung *

 

Abstract

In this work, Debye-Waller factors (DWFs) of semiconductor elements in their compounds have been studied based on statistical moment method. The DWFs are presented by the mean square displacement (MSD) which has close relation with the mean square relative displacement (MSRD). Their analytical expressions have been derived based on statistical moment method and empirical many-body Stillinger-Weber potentials. Numerical results for the MSDs of semicnductor elements in GaAs, GaP, InP, InSb having zinc-blende structure are found to be in reasonable agreement with experiment and with those of other theories. They show that the MSD describing thermodynamic properties of a semiconductor element becomes different when it is mixed with different other semiconductor elements to be compounds.

 

Keywords:  Debye-Waller factor, statistical moment method, Stillinger-Weber potential,  semiconductor compound.

Received

  Accepted
01 November 2016
09 December 2016
 

Wien Effect in Molten LaCl3, CeCl3 and NdCl3

Original Research

Journal of Chemistry and Materials Research Vol. 5 (6), 2016, 115–118

O.M. Shabanov*, S.I. Suleymanov, A.O. Magomedova, Ka.N. Ashurbekova

 

Abstract

The electrical conductivity of molten lanthanum, cerium and neodymium chlorides rise with increasing electrical field intensity and strive to achieve the limiting values in the fields of the order of 1 MV/m. The field conductance quotient achieves the hundreds of percent. The limiting high-voltage conductivity of the melts obeys the Nernst-Einstein. The results obrained indicate the stimulated dissociation of these structured melts.

 

Keywords: Electrical conductivity; Molten lanthanide chlorides; Limiting conductivity; Wien effect.

Received
Accepted
01 December 2016
20 December 2016
 

Preparation and Characterization of p‒Type Semiconducting NiO Thin Films Deposited by Sol‒Gel Technique

Original Research

Journal of Chemistry and Materials Research Vol. 5 (6), 2016, 119–122

Said Benramache* and Mansour Aouassa

 

Abstract

In present paper, NiO thin films were prepared by sol-gel spin coating technique onto glass substrates at different solution molarities.  For the result of XRD analysis reveals that NiO films showed good crystallinity and strong orientation along (200) direction at 0.8 M. for high molarities the thin films showed high transmission property (over 88 %) in the visible wavelength region. The optical band gap was found to be in the range of 3.975–3.980 eV depending on the concentration. The minimum of Urbach energy was obtained at 0.7 mol/l. The electrical conductivity of our films in the order 0.2 (Ω.cm)-1. The best estimated structure, optical and electrical characterisations are achieved in NiO film with 0.8 M.

 

Keywords: NiO; Thin films; Molarity; Spin‒Coating method.

Received
 Accepted
27 November 2016
20 December 2016
 

Influence of Deposition Medium on the Optical Properties of NixOy Thin Films

Original Research

Journal of Chemistry and Materials Research Vol. 5 (6), 2016, 123–128

M.P. Orji, A.N.C. Agbogu, and A.B.C. Ekwealor

 

Abstract

Chemical bath deposition technique was successfully employed for the deposition of nanocrystalline nickel oxide (NiO) thin films in different media and changes in their optical properties studied. The structural property of the films obtained from X-ray diffraction (XRD) analyses showed that the films were crystallized and have rhombohedral structure. The elemental composition was deduced from Rutherford back scattering spectroscopy (RBS). Investigation into the optical properties of the films revealed that they were irregularly influenced by deposition media. The band-gap of the films ranged from 2.20 – 2.70eV, while their refractive index values ranged from 1.1 – 2.4.

 

Keywords: Nickel oxide; deposition medium; Nanocrystalline; RBS.

Received
 Accepted
07 October 2016
20 December 2016
 

Crucial Role of Undoped/Doped State of Polyaniline‒β‒Cyclodextrin Composite Materials in Determining Sensor Functionality Toward Benzene/Toluene Toxic Vapor

Original Research

Journal of Chemistry and Materials Research Vol. 5 (6), 2016, 129–134

E. Subramanian*, B. Mercy Leela Jeyarani, C. Murugan, and D. Pathinettam Padiyan

 

Abstract

Present work reports the development of sensor material for benzene/toluene vapor functional at ambience. Pristine polyaniline and its composite with β-cyclodextrin (CD) both in undoped form and the doped polyaniline-CD composite material were synthesized in aqueous or in 0.1 M sulfuric acid medium respectively. Conductivity, FTIR, UV-Vis, XRD and SEM characterizations confirmed the undoped/doped state of the material. On application to sensing of benzene/toluene analyte, the two undoped materials performed well with about 39-57% sensor efficiency and mostly non-linear sensor behavior while the doped material with 6 – 7 orders of higher conductivity had insignificant sensitivity. The hydrophilicity imparted through doping process was found mainly responsible for this behavior. The undoped materials relatively in a non-polar/hydrophobic environment could detect the analyte. Inclusion complex with CD having greater hydrophobicity enhanced the sensor response of polyaniline toward analyte. Undoped/doped state thus became crucial in determining the sensor functionality of polyaniline-CD composite materials.

 

Keywords: Polyaniline, β-cyclodextrin, chemo-sensor, benzene/toluene analyte, undoped/doped state, non-linear response.

Received
 Accepted
06 November 2016
  24 December 2016