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Diouri, J.; Jp, Lascaray; Me, Amrani

doi:10.1103/physrevb.31.7995

Cited by 139 publications

(39 citation statements)

References 17 publications

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“…A shifting of band edge energy due to exchange interaction of electrons in conduction band and valence band with the d electrons of Mn (dopant) was invoked to explain the variation in the band gap with dopant concentration. Diouri et al [34] and Bylsma et al [33] have shown that for an alloy in its paramagnetic phase, as a result of second order perturbation of exchange interaction between the Mn +2 ion and the band electron, i.e., s−d and p−d interaction gives rise to negative and positive correction to the energy of conduction and valence band, respectively and causes a red−shift of the band gap with increasing x. For antiferromagnetic phase the effect of ex− change interaction changes so as to produce a blue shift [35].…”

Section: Transmission and Optical Band Gapmentioning

confidence: 99%

Enhancement in UV emission and band gap by Fe doping in ZnO thin films

Srivastava

Kumar

Khare

2014

Opto-Electronics Review

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Enhancement of the optical band gap of ZnO from 3.14 to 3.29 eV has been obtained using Fe dopant. Undoped and doped ZnO films are deposited by sol-gel spin coating. XRD patterns indicate polycrystalline nature and hexagonal wurtzite structure of Zn1−xFexO films. EDX analysis confirms the presence of iron dopant. The photoluminescence spectra show an ultraviolet emission peak at 398 nm (NBE emission) and defect emission peak at 485 nm. Intensity of the NBE emission is much higher for the doped samples with its ratio to defect emission intensity highest for 2 at. %doping. The NBE emission shifts to higher energy with increasing dopant concentration in a manner similar to that exhibited by the band gap. Surface morphology has been studied using FESEM.

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Section: Transmission and Optical Band Gapmentioning

confidence: 99%

Enhancement in UV emission and band gap by Fe doping in ZnO thin films

Srivastava

Kumar

Khare

2014

Opto-Electronics Review

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“…Diouri et al [22] attributed the band-gap decrease of transition-metal ion doped II-VI semiconductors to the sp-d spin-exchange interactions between the band electrons and the localized d electrons of the transition-metal ion substituting the cation. The potential fluctuation introduced by ionised impurities leads to the band tailing of the valence band and conduction bands and contributes to the band gap narrowing.…”

Section: Uv-visible Absorption Spectrummentioning

confidence: 99%

Structural, EPR, photo and thermoluminescence properties of ZnO:Fe nanoparticles

Reddy

Kokila

Nagabhushana

et al. 2012

Materials Chemistry and Physics

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a b s t r a c tZn (1−x) Fe (x) O (1+0.5x) (x = 0.5-5 mol%) nanoparticles were synthesized by a low temperature solution combustion route. The structural characterization of these nanoparticles by PXRD, SEM and TEM confirmed the phase purity of the samples and indicated a reduction in the particle size with increase in Fe content. A small increase in micro strain in the Fe doped nanocrystals is observed from W-H plots. EPR spectrum exhibits an intense resonance signal with effective g values at g ≈ 2.0 with a sextet hyperfine structure (hfs) besides a weak signal at g ≈ 4.13. The signal at g ≈ 2.0 with a sextet hyperfine structure might be due to manganese impurity where as the resonance signal at g ≈ 4.13 is due to iron. The optical band gap E g was found to decrease with increase of Fe content. Raman spectra exhibit two non-polar optical phonon (E 2 ) modes at low and high frequencies at 100 and 435 cm −1 in Fe doped samples. These modes broaden and disappear with increase of Fe dopant concentration. TL measurements of ␥-irradiated (1-5 kGy) samples show a main glow peak at 368• C at a warming rate of 6.7• Cs −1 . The thermal activation parameters were estimated from Glow peak shape method. The average activation energy was found to be in the range 0.34-2.81 eV.

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“…The exchange interaction between the bottom of the conduction band and the upper conduction band states as well as interaction between the top of the valence band and the lower valence band states yields a red shift of the energy gap [9,2,3,7]. This red shift is proportional to the spin correlation function and the strength of the exchange interaction.…”

mentioning

confidence: 97%

“…These effects were observed in bulk CdMnTe [2][3][4], ZnMnTe [5], ZnMnSe [6,7] and CdMnS [8]. The exchange contribution to the energy gap reflects a correlation between spins of the magnetic ions [9,3,7] and, therefore, it is particularly important in concentrated alloys possessing magnetically ordered (spin-glass or antiferromagnetic) phases [1].…”

mentioning

confidence: 99%

“…Variation with temperature of the energy gap in DMS (as well as in magnetic semiconduction [14]) results from two effects: a nonmagnetic effect, reflecting phonon-induced lattice constant variation with T, typical of nonmagnetic semiconduction [15] and the mentioned above exchange correction to the conduction and valence bands [9,2,3,16]. The exchange interaction between the bottom of the conduction band and the upper conduction band states as well as interaction between the top of the valence band and the lower valence band states yields a red shift of the energy gap [9,2,3,7].…”

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confidence: 99%

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Temperature Dependence of Energy Gap of Highly Concentrated Cd_1-xMn_xTe(0.6 < x ≤ 1.0) Epilayers

et al. 1995

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The temperature dependence of the energy gap of MBE grown Cd1-x Mnx Τe (0.6 < x < 1.0) was measured for 2 K < Τ < 200 K and B < 5 Τ. The results are interpreted in the frames of the model predicting that the exchange contribution to the band edge shift is proportional to the product of the magnetic susceptibility and the temperature. 4,10]. In this communication we report on the energy gap variation with the temperature in Cd1-xMnxTe epilayers with Mn concentration ranging from x = 0.6 to x = 1.0 (i.e. in cubic MnTe).The samples used for the present study were grown by MBE technique as a few microns (< 5 μm) thick epilayers of cubic Cd 1 -x Mn x Te, on GaAs substrate.The manganese concentration was x = 0.66, 0.73, 0.85 and 1.0 (MnTe), as determined from the epilayer lattice constant. We measured the reflectance in the free exciton range for 2 K -< Τ < 200 K and magnetic flelds B < 5 Τ. In most cases the excitonic stuctures were not viSible in a standard reflectance experiment, irrespective of the applied magnetic field, most probably due to large exciton line width (913)

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Effect of the magnetic order on the optical-absorption edge inCd1−xMn

Cited by 139 publications

References 17 publications

Enhancement in UV emission and band gap by Fe doping in ZnO thin films

Enhancement in UV emission and band gap by Fe doping in ZnO thin films

Structural, EPR, photo and thermoluminescence properties of ZnO:Fe nanoparticles

Temperature Dependence of Energy Gap of Highly Concentrated Cd_1-xMn_xTe(0.6 < x ≤ 1.0) Epilayers

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Effect of the magnetic order on the optical-absorption edge inCd1−xMn

Cited by 139 publications

References 17 publications

Enhancement in UV emission and band gap by Fe doping in ZnO thin films

Enhancement in UV emission and band gap by Fe doping in ZnO thin films

Structural, EPR, photo and thermoluminescence properties of ZnO:Fe nanoparticles

Temperature Dependence of Energy Gap of Highly Concentrated Cd1-xMnxTe(0.6 < x ≤ 1.0) Epilayers

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Product

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Temperature Dependence of Energy Gap of Highly Concentrated Cd_1-xMn_xTe(0.6 < x ≤ 1.0) Epilayers