0000000000359065

AUTHOR

H. S. Güder

showing 3 related works from this author

Pressure and temperature dependence of the band-gap in CdTe

2003

In this paper we report on isothermal compression measurements (up to 5 GPa and 500 K) of the optical absorption edge of 1 μm epitaxial layers of CdTe growth by metalorganic chemical vapor deposition (MOCVD) on GaS substrates. The isothermal blue shift under pressure of the direct energy gap (Γ v 15 → Γ c 1 ) in the zinc-blende phase is about 7.1 × 10 -2 eV GPa -1 and is found to be independent of temperature within the experimental errors. The isobaric red shift in the stability range of the zinc-blende phase is about -3.76 × 10 -4 eV K -1 . Regarding the phase transitions, no discontinuity in the energy gap has been found in the narrow pressure range where the cinnabar phase can be presen…

Phase transitionAbsorption spectroscopybusiness.industryBand gapChemistryAnalytical chemistryCondensed Matter PhysicsIsothermal processElectronic Optical and Magnetic MaterialsBlueshiftOpticsAbsorption edgeIsobaric processMetalorganic vapour phase epitaxybusinessphysica status solidi (b)
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Pressure Dependence of the Bandgap Bowing in Zinc-Blende ZnTe 1− x Se x

2002

We report on the pressure dependence of the bandgap bowing in the ZnTe 1 m x Se x alloy, in the whole composition range. The bandgap bowing parameter is shown to increase almost linearly with pressure from 1.23 at ambient pressure to 1.6 at 7 GPa. Saturation effects observed in the pressure dependence for x =0.1 and x =0.2 are shown to be related to the direct-to-indirect crossover. Results are discussed and interpreted in the framework of structural relaxation models for gap bowing. A prediction of these models (the negative bowing of the o 15 m ;X 1 transition) is shown to be compatible with the fact that the direct-to-indirect crossover pressure increases with the Se content.

Materials scienceCondensed matter physicsBand gapBowingRelaxation (NMR)Alloychemistry.chemical_elementZincPressure dependenceengineering.materialCondensed Matter PhysicschemistryengineeringSaturation (magnetic)Ambient pressureHigh Pressure Research
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Electronic structure and optical properties of CdTe rock-salt high pressure phase

2003

This paper reports on optical absorption and reflectance measurements in thin CdTe samples up to 15 GPa. All studied samples become virtually opaque at the pressure transition between the zinc-blende and rock-salt phases (3.9 GPa). As pressure increases up to 10 GPa, a relative transparency region is observed between 1.2 eV and 2.4 eV, whose high energy edge shifts to higher photon energies. Above 10 GPa the transparency region gradually shrinks and disappears at about 11 GPa. The low energy side of the absorption spectrum is attributed to free carrier absorption, as electronic structure calculations show that rock-salt CdTe is a semimetal or a low gap semiconductor. Band filling effects lo…

Phase transitionAbsorption spectroscopyCondensed matter physicsbusiness.industryChemistryBand gapCondensed Matter PhysicsSemimetalElectronic Optical and Magnetic MaterialsOpticsAttenuation coefficientPhase (matter)Free carrier absorptionAbsorption (electromagnetic radiation)businessphysica status solidi (b)
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