GGD SD College

Chandigarh, India

GGD SD College

Chandigarh, India

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Kumar A.,Panjab University | Lal M.,GGD SD College | Sharma K.,Panjab University | Tripathi S.K.,Panjab University | Goyal N.,Panjab University
Indian Journal of Pure and Applied Physics | Year: 2013

The temperature dependence of dc conductivity of Se85-xTe 15Gex (x=0, 2, 6, 10, 15) chalcogenide glasses in the temperature range 273-333 K, has been reported. The dc conductivity varies exponentially with temperature for all compositions. The log σdc versus 1000/T plots are almost straight lines in whole studied temperature range indicating a singly activated phenomenon with single activation energy. Meyer-Neldel rule between pre-exponential factor and activation energy has been observed. Meyer-Neldel characteristic energy (EMN) and 00 come out to be 40.67 meV and 3.78*10-6 S cm -1, respectively.Both values lie in the range predicted by Shimakawa and Abdul-Waheb for chalcogenide glasses.


Kumar A.,Panjab University | Lal M.,GGD SD College | Sharma K.,Panjab University | Navdeep G.,Panjab University
Chalcogenide Letters | Year: 2013

Frequency and temperature dependent ac conductivity studies of Se85-x Te15Gex (x= 0, 2, 6, 10, 15) glasses have been reported. Results indicate that Se83 Te15 Ge2 obeys well established relation aaca< frequency exponent s is found to decrease with increase in temperature and results have been explained as the basis of correlated barrier hopping (CBH) model and numerical calculations agree well with experimental results. But a different type of behavior has been observed for Se85-x Te15Gex(x = 6, 10, 15). Distinct peaks have been observed in the plots of temperature dependence of ac conductivity for Se85-x Te15Gex (x = 10, 15). The results have been interpreted using CHB and "simple pair" model. Ge introduced localized states deep in the band gap and form simple pairs. Theoretical results obtained by using these models have been found to be in agreement with experimental results.


Gangahar M.,GGD SD College
AI and Society | Year: 2013

How does one begin to define the global identity? How does globalization offers a sense of identity, a sense of belonging, to an individual, in particular a non-westerner? Has globalization given a new identity to the erstwhile-colonized subject, who had been holding on tightly to the idea of nationalism that offered him an identity-passport into the world? My paper explores the contestation of identity-culturally-in the globalized world. It argues that cultural identity remains in a flux, whatever may the context be. From the period of colonialism to that when nation was regarded as the foremost structure of collective identity, which then defined the self, and finally in the era that we call as the modern or the postmodern period, or even globalization, identity is pushed toward liminality. © 2013 Springer-Verlag London.


Kumar A.,Panjab University | Kumar A.,PG Government College for Girls | Lal M.,GGD SD College | Sharma K.,Panjab University | And 2 more authors.
Chalcogenide Letters | Year: 2014

Temperature and frequency dependence of dielectric constant(ε') and dielectric loss(ε") have been studied for chalcogenide glasses Se85-xTe15Gex (x= 0, 2, 6, 10, 15) by measuring capacitance and conductance in the frequency range 5 kHz to 20 kHz and temperature range 253K to 313K. Dielectric dispersion has been found to occur in this frequency and temperature range. The variation of dielectric constant and dielectric loss with temperature shows almost similar behavior for x=0, 2, 6, but dielectric constant and dielectric loss show peaks for x=10, 15. The analysis of results indicates that dielectric losses are dipolar in nature and are explained on the basis of Guintini's theory of dielectric dispersion based on two electron hopping over a potential barrier. Results show that both dielectric constant and dielectric loss decrease with increase in Germanium concentration. This is due to the decrease in defect states with increase in Germanium concentration.


Kumar A.,Panjab University | Kumar A.,Post Graduate Government College for Girls | Singh G.,GGD SD College | Lal M.,GGD SD College | And 2 more authors.
AIP Conference Proceedings | Year: 2011

In this paper we report the frequency and temperature dependence of ac conductivity and dielectric studies of Se85-xTe15In x glasses. The measurements have been made on Se 85-xTe15Inx (x=2, 6, 10, 15) in the frequency range 2 kHz to 50 kHz and temperature range 203 K and 313 K. Results indicate that dielectric dispersion occurs in this frequency and temperature range. The results have been explained on the basis of correlated Barrier Hopping (CBH) model. The dc conductivity increases with increase in temperature for all composition. The Log σdc versus 1000/T plots are almost straight lines in whole studied temperature range indicative of singly activated phenomena having single activation energy. © 2011 American Institute of Physics.


Goyal N.,Panjab University | Lal M.,GGD SD College | Kumar A.,Post Graduate Government College for Girls | Tripathi S.K.,Panjab University
AIP Conference Proceedings | Year: 2011

AgInSe2 is a material of special interest, since it is a ternary analog of CdS which has been used for a number of optoelectronic devices. Material has been studied over a wide range of frequencies (5 kHz to 1 MHz), through measurements of conductance and capacitance, at different temperatures and light intensities. The results indicate that there is an increase in capacitance (C) as well as conductance (G), when sample is exposed to light radiations at a given temperature. The switching and recovery time has been analysed in terms of time constant (τ=C/G) and found to be of the order of micro seconds. It has been further observed that switching response is faster at higher frequencies and its dependence on temperature decreases at these frequencies. It is understandable, because higher the rate of recombination of optically/thermally generated carriers, lesser should be the value of τ. © 2011 American Institute of Physics.


Sharma K.,Panjab University | Sharma K.,GGD SD College | Kumar A.,Panjab University | Goyal N.,Panjab University | Lal M.,GGD SD College
AIP Conference Proceedings | Year: 2013

This paper reports the preparation and characterization of Bi 2Te3, and (Bi.20Sb.80) 2Te3. The materials are characterized by using X-ray diffraction and Fourier transform-infrared spectroscopy (FT-IR). The XRD pattern reveals that materials are nanocrystalline in nature, Bi2Te 3 possesses rhombohedral crystal structure and (Bi .20Te.80)2Te3 possesses tetragonal crystal structure. Optical characterization has been done and parameters likes absorption coefficient and band gap Eg has been calculated from FT-IR spectroscopy. © 2013 AIP Publishing LLC.

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