The dielectric function and interband transitions in

Castaing, O.; Granger, R.; Benhlal, J.T.; Triboulet, R.

doi:10.1088/0953-8984/8/31/009

Cited by 20 publications

(6 citation statements)

References 44 publications

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“…Although there has been greater emphasis on the characterization and development of single crystals of Cd 1-x Zn x Te with low Zn content as electronic materials [5,6], polycrystalline compound thin films have received considerable attention because of the tunability of the band gap and lattice parameter with composition (Zn), which has increased the applications in the fields of photodetectors and solar cells [7,8]. A literature survey reveals that studies on polycrystalline Cd 1-x Zn x Te thin films are concerned with the electrical characterization based on dc measurements and optical properties of Cd 1-x Zn x Te single crystals [9][10][11]. However, to our knowledge, detailed studies on the dielectric relaxation and electric modulus analysis of vacuum evaporated Cd 1-x Zn x Te thin films have not been made, although dielectric relaxation studies give important information about various factors contributing to the overall conduction mechanism.…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of Cd0.6Zn0.4Te thin films

Prabakar

Narayandass

Mangalaraj

2003

phys. stat. sol. (a)

121

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PACS 73.50.Dn, 77.22.Ch, 81.15.Ef Cd 0.6 Zn 0.4 Te thin films of different thicknesses were prepared by the thermal evaporation technique onto well-cleaned Corning glass substrates. The dielectric properties of Al/Cd 0.6 Zn 0.4 Te/Al sandwich structures were studied in the frequency range 50 Hz -4 MHz and in the temperature range 300 -420 K. The effect of thickness on the net dielectric constant was studied in detail. The bulk dielectric constant was calculated as 13.5, which is consistent with the value of 11.5 -8.2 measured at 1 MHz for the films of different thickness varying between 120 and 850 nm. The relaxation phenomenon present in the films is due to the presence of grains and grain boundaries across the film thickness. The relaxation times decrease with increasing measuring temperatures, suggesting that the net relaxation phenomenon is associated with the charge carrier transport mechanism. The grain boundary activation energies, calculated from the spectroscopic plot, vary between 0.61 and 0.53 eV. The variation of conductivity as a function of temperature and frequency reveals non-adiabatic hopping of charge carriers between impurity sites/localized states and the activation energies are found to vary between 0.28 and 0.11 eV.

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Section: Introductionmentioning

confidence: 99%

Dielectric properties of Cd0.6Zn0.4Te thin films

Prabakar

Narayandass

Mangalaraj

2003

phys. stat. sol. (a)

121

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“…Since optical response is of great importance for many device applications, many efforts have been made to obtain optical response and, consequently, to determine the optical constants of ZnTe [1]. Recent spectroellipsometry (SE) studies on ZnTe have proven to be useful for determining the optical constants and deducing the critical-point (CP) parameters in this material [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Photoreflectance study in theE₁andE₁+Delta₁transition regions of ZnTe

Kaneta

Adachi

2000

J. Phys. D: Appl. Phys.

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Photoreflectance spectra have been measured to determine the E 1 and E 1 + 1 energies in ZnTe at temperatures T between 77 and 300 K using an Ar + -ion laser as a modulation light source. The measured photoreflectance spectra can be successfully explained by an excitonic line shape. The temperature dependence of the E 1 and E 1 + 1 critical-point parameters (energy, amplitude and broadening parameter) have been analysed using the Varshni equation and an empirical expression of the Bose-Einstein type.

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“…[8][9][10] Table I shows the values found from Ref. [8][9][10] Table I shows the values found from Ref.…”

Section: Introductionmentioning

confidence: 99%

In-situ control of temperature and alloy composition of Cd1−xZnxTe grown by molecular beam epitaxy

Daraselia

Brill

Garland

et al. 2000

Journal of Elec Materi

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In this work in-situ spectroscopic ellipsometry (SE) has been applied for the simultaneous determination of the growth temperature and alloy composition for the epitaxial Cd 1-x Zn x Te(211)/Si(211) structure. The optical dielectric functions of CdTe and Cd 0.96 Zn 0.04 Te (CZT) epilayers were studied as a function of temperature both ex-situ and in-situ in the range from 1.6 eV to 4.5 eV. We employed parametric models for the simulation of the optical properties of CZT at and between the critical points (CP) E 0 , E 0 + ∆ 0 , E 1 , E 1 + ∆ 1 , E 2 (∑) and E 2 (Σ). Critical point energies and line widths for Cd 1-x Zn x Te were obtained through the fitting process, which included both zero order and higher order derivatives of the SE pseudo dielectric function. The dependence of the different critical points on Zn concentration x is discussed. It has been demonstrated that the energy of the weak E 0 + ∆ 0 transition can be used to measure composition, while the E 1 energy can be used as a real-time temperature measure. The model parameters were optimized through the simultaneous analysis of multiple data sets, and the temperature dependent model was developed for in-situ application. Our analysis is estimated to produce uncertainties of only ±0.5°C in measuring the temperature and ±0.5% in measuring the composition if only the zero order dielectric function is being fitted. The effects of a surface overlayer, of reflected beam deflections, and of other experimental problems on the overall accuracy, are discussed as well as ways to improve the in-situ SE data quality.

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The dielectric function and interband transitions in

Cited by 20 publications

References 44 publications

Dielectric properties of Cd0.6Zn0.4Te thin films

Dielectric properties of Cd0.6Zn0.4Te thin films

Photoreflectance study in theE₁andE₁+Delta₁transition regions of ZnTe

In-situ control of temperature and alloy composition of Cd1−xZnxTe grown by molecular beam epitaxy

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The dielectric function and interband transitions in

Cited by 20 publications

References 44 publications

Dielectric properties of Cd0.6Zn0.4Te thin films

Dielectric properties of Cd0.6Zn0.4Te thin films

Photoreflectance study in theE1andE1+Delta1transition regions of ZnTe

In-situ control of temperature and alloy composition of Cd1−xZnxTe grown by molecular beam epitaxy

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Photoreflectance study in theE₁andE₁+Delta₁transition regions of ZnTe