A study of the structural, electrical and optical properties of copper tellurium oxide glasses

Hassan, Moukhtar A.; Hogarth, C. A.

doi:10.1007/bf01111908

Cited by 150 publications

(53 citation statements)

References 4 publications

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“…The least ∆E i.e., sharp absorption edge suggests that the defects are minimum facilitating long-range order. The main feature of the absorption edge of amorphous semiconductors, particularly at the lower values of absorption coefficient is an exponential increase of the absorption coefficient α(ν) with photon energy in accordance with an empirical relation [49] …”

Section: Optical Band Gap (E Opt ) and Urbach Energies (∆E)mentioning

confidence: 77%

Chromium ions in alkali lead borotellurite glasses – An EPR and optical study

Chakradhar

Rao

Sivaramaiah

et al. 2005

Physica Status Solidi (b)

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Chromium ions doped 90 Na 2 B 4 O 7 + (9 -x)PbO + 1TeO 2 and 90 K 2 B 4 O 7 + (9 -x)PbO + 1TeO 2 (x = 3, 4, 5, 6, 7 and 8 mol%) glasses have been studied by using Electron Paramagnetic Resonance (EPR) and optical absorption techniques. The EPR spectra exhibit a broad resonance signal at g = 4.65 and a narrow resonance signal at g = 1.97. The resonance at g = 4.65 can be attributed to isolated Cr 3+ ions in rhombic symmetry subjected to strong crystal field effects and the resonance at g = 1.97 is due to Cr 5+ ions. The EPR spectra have also been studied at different temperatures (153 -393 K). The number of spins (N) participating in the resonance is measured as a function of temperature and the activation energy is calculated. The exchange coupling constant J between chromium ions is calculated. The optical absorption spectrum exhibits bands characteristic of Cr 3+ ions in an octahedral symmetry. The optical band gap (E opt ) and Urbach energies (∆E) have been calculated for all the glass samples and it is observed that E opt decreases and ∆E increases with increase of chromium content. This has been explained as due to the creation of additional localized states with chromium doping, which overlap and extend in the mobility gap of the glass matrix.

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Section: Optical Band Gap (E Opt ) and Urbach Energies (∆E)mentioning

confidence: 77%

Chromium ions in alkali lead borotellurite glasses – An EPR and optical study

Chakradhar

Rao

Sivaramaiah

et al. 2005

Physica Status Solidi (b)

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show abstract

“…In order to examine the optical band gap energy for the LDS glasses and glass ceramics, the optical absorption spectra were also recorded in the near ultra-violet region. The main feature of the absorption edge of amorphous semiconductors, particularly at the lower values of the absorption coefficient, is an exponential increase of the absorption coefficient ˛ ( ) with photon energy h in accordance with an empirical relation [36]:…”

Section: Optical Studiesmentioning

confidence: 86%

Microstructure, mechanical, EPR and optical properties of lithium disilicate glasses and glass–ceramics doped with Mn2+ ions

Molla

Chakradhar

Kesavulu

et al. 2012

Journal of Alloys and Compounds

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“…This shift of band edge towards the visible region of the spectrum absorbing violet and weakening the blue with the increase of TiO 2 content imparts strong yellow color tint to the glasses. In the Urbach region of the energy band gap, the absorption coefficient (˛) varies following the relation [28]:…”

Section: Resultsmentioning

confidence: 99%