Cu2 O nanoparticles with diameters in the range 6.0-8.6 nm were prepared by a chemical method. Both dc and ac electrical properties were measured on a compacted nanoparticle assembly. dc electrical resistivity in the temperature range 140-300 K was found to arise due to a variable range hopping conduction mechanism. The ac resistivity variation as a function of frequency (in the range 10 kHz to 3 MHz) and temperature (range 220-320 K) was explained on the basis of the power-law exponent in percolating clusters. The interfacial amorphous phase of the nanoparticle assembly appears to control the electrical behavior of the system. © 2005 American Institute of Physics.

SOURISH BANERJEE

Physics

A BOSE

S BASU

D CHAKRAVORTY

Fulltext

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Electrical properties of compacted assembly of copper oxide nanoparticles

Journal of Applied Physics

DC electrical measurements were carried out on compacted powders of magnetite with an average particle diameter of 50 nm over the temperature range 10-300 K. The non-stoichiometry was estimated from Mossbauer spectroscopy analysis. High-resolution X-ray diffraction studies in the temperature range 93-300 K did not show any phase transition. There was a drastic change in resistivity around 80 K but no discontinuity thereof. Electrical resistivity vs. temperature data were analysed on the basis of Mott's small polaron and variable-range hopping models, respectively. The Verwey temperature as estimated from this analysis was 93 K. From voltage-current characteristics it was concluded that there was a small intrinsic gap at the Fermi level above the transition temperature and the same increased drastically below the transition temperature. This was ascribed to a transition from short-range order to long-range order as the temperature was lowered. © 2008 Elsevier B.V. All rights reserved.

Journal of Magnetism and Magnetic Materials

Electrical properties of nanocrystalline magnetite with large non-stoichiometry, near Verwey transition

We have investigated the temperature dependent carrier transport properties of nano-crystalline copper nitride thin films synthesized by modified activated reactive evaporation. The films, prepared in a Cu-rich growth condition are found to be highly disordered and the carrier transport in these films is mainly attributed to the impurity band conduction. We have observed that no single conduction mechanism is appropriate to elucidate the carrier transport in the entire temperature range of 20 - 300 K. Therefore, we have employed different conduction mechanisms in different temperature regimes. The carrier transport of the films in the low temperature regime (20 - 150 K) has been interpreted by implementing quantum correction to the conductivity. In the high temperature regime (200 - 300 K), the conduction mechanism has been successfully analyzed on the basis of Mott's variable range hopping mechanism. Furthermore, it can be predicted that copper ions present at the surface of the crystallites are responsible for the hopping conduction mechanism. ï¿½ 2015 Author(s).

AIP Advances

Evidence of quantum correction to conductivity and variable range hopping conduction in nano-crystalline Cu3N thin film

Cuprous oxide (Cu2O) particles coated with polyacrylamide having diameters in the range from 4.8 to 8.6 nm were prepared by a chemical method. The optical absorption of these particles was found to be characterized by excitons with corresponding energies varying from 2.6 to 2.25 eV in the particle size range mentioned above. A second optical-absorption maximum signifying surface states within the band gap is exhibited by the specimens with relevant energies varying from 2.6 to 1.77 eV in this particle size range.

Europhysics Letters

Optical absorption by nanoparticles of Cu2O

Physical Review Letters

Mørup and Frandsen Reply:

Anisotropic Metal-Insulator Transition in Epitaxial Thin Films

Nature

A three-dimensional optical photonic crystal with designed point defects

Evidence for Luttinger-Liquid Behavior in Crossed Metallic Single-Wall Nanotubes

Journal	Journal of Applied Physics
Publisher	AMER INST PHYSICS
ISSN	0021-8979
Open Access	No