Temperature dependence of the shifts and broadenings of the critical points in GaAs

Gopalan, Sudha; Lautenschlager, P.; Cardona, M.

doi:10.1103/physrevb.35.5577

Cited by 137 publications

(82 citation statements)

References 20 publications

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“…As one can see, broadenings of the critical point E 1 calculated in this work are in satisfactory agreement with the experimental results of Ref. 7. In the case of our calculation, the agreement is best with the experimental data obtained by fit with the Fano-type excitonic shape, whereas the previous theoretical result of Ref.…”

Section: Broadening Of the E1 Critical Pointsupporting

confidence: 78%

“…6, we have estimated the broadening of the critical point E 2 in GaAs. In the case of E 2 , our results (solid line) are very different from the theoretical result obtained with the empirical pseudopotential method 7 , and yield a much better agreement with experiment, showing that the experimentally measured broadening of the E 2 point can be attributed to the electron-phonon scattering. It must be noted down, however, first that only experimental results extracted with the fit with the twodimensional critical point model are available in this case.…”

Section: Broadening Of the E2 Critical Pointcontrasting

confidence: 49%

“…In many cases, the electron-phonon coupling determines the magnitude of the lifetimes of electronic states inside the band gap, and the widths of the corresponding absorption peaks [4][5][6] . It is also responsible for shifts and broadenings of the interband critical points in semiconductors 7,8 . The interpretation and analysis of the (ultra)fast dynamics of relaxation of photoexcited electrons is particularly difficult, because many relaxation processes are present simultaneously, and disentangling their respective contributions requires ad hoc information on their relative importance and order of magnitude 9 .…”

Section: Introductionmentioning

confidence: 99%

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Wannier interpolation of the electron-phonon matrix elements in polar semiconductors: Polar-optical coupling in GaAs

et al. 2015

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We generalize the Wannier interpolation of the electron-phonon matrix elements to the case of polar-optical coupling in polar semiconductors. We verify our methodological developments against experiments, by calculating the widths of the electronic bands due to electron-phonon scattering in GaAs, the prototype polar semiconductor. The calculated widths are then used to estimate the broadenings of excitons at critical points in GaAs and the electron-phonon relaxation times of hot electrons. Our findings are in good agreement with available experimental data. Finally, we demonstrate that while the Fröhlich interaction is the dominant scattering process for electrons/holes close to the valley minima, in agreement with low-field transport results, at higher energies, the intervalley scattering dominates the relaxation dynamics of hot electrons or holes. The capability of interpolating the polar-optical coupling opens new perspectives in the calculation of optical absorption and transport properties in semiconductors and thermoelectrics.

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Section: Broadening Of the E1 Critical Pointsupporting

confidence: 78%

Section: Broadening Of the E2 Critical Pointcontrasting

confidence: 49%

Section: Introductionmentioning

confidence: 99%

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Wannier interpolation of the electron-phonon matrix elements in polar semiconductors: Polar-optical coupling in GaAs

et al. 2015

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“…16 The results show that ␣ should be negative in GaAs as well, especially due to the lifetime broadening effect.…”

Section: ͑1͒mentioning

confidence: 94%

High temperature mobility of CdTe

Franc

Grill

Turjanska

et al. 2001

Journal of Applied Physics

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The Hall mobility of electrons H is measured in CdTe in the temperature interval 450-1050°C and defined Cd overpressure in near-intrinsic conditions. The strong decrease of H above 600°C is reported. The effect is explained within a model of multivalley conduction where both electrons in ⌫ 1c minimum and in L 1c minima participate. The theoretical description is based on the solution of the Boltzmann transport equation within the relaxation time approximation including the polar and acoustic phonon intravalley and intervalley scatterings. The ⌫ 1c to L 1c separation ⌬Eϭ0.29 Ϫ10 Ϫ4 T ͑eV͒ for the effective mass in the L valley m L ϭ0.35m 0 is found to best fit the experimental data. Such ⌬E is about four times smaller than it is predicted by first-principle calculations. The recent progress in high technology brings a renewed interest to the research of the basic properties of CdTe ͑CT͒. 1,2 The purpose of this communication is a study of high temperature near intrinsic mobility evaluated from in situ measurements of Hall coefficient R H and conductivity .In our method the content of Cd in the sample changes due to the sublimation from the free surface. The equilibrium is controlled here by a proper Cd overpressure which is established in the two-zone furnace by a temperature of the Cd source. The advantage of this arrangement is the possibility of measuring properties of CT in the phase P -T diagram both in intrinsic conditions and under Cd or Te overpressure. The measurement of R H and is performed depending on the pressure and temperature of Cd when the equilibrium concentration of electrically active defects is established by diffusion processes. Experimental data show as expected, that R H and depend both on pressure of Cd and temperature, but the H is near intrinsic conditions practically independent of Cd pressure P Cd . It implies that there is no important impurity scattering in this case. Figure 1 shows the phase P -T diagram for CT with a marked region of stability of CT, where our measurements were performed ͑Cd-rich area of the phase diagram͒.The measurement was performed on samples from single crystals prepared by vertical cooling in the temperature gradient. The high temperature measurements were done in a quartz ampoule with a diameter 17 mm located in a furnace between poles of an electromagnet. It was possible to keep the sample temperature with the precision of about 1°C and to change the gas pressure of one of the components ͑in our case Cd͒ in the interval 2ϫ10 Ϫ4 Ϫ2 atm. The sample with tungsten or molybdenum spring contacts in the van der Pauw configuration was placed in a quartz holder together with the Pt-PtRh thermocouple.In this communication we shall concentrate on electrons because the influence of holes is weak and can be included in a simple, standard way. The basic problem at the evaluation of the drift electron mobility at temperatures ͑500-1000°C͒ is the determination of scattering mechanisms, which participate in scattering of current carriers. A number of detailed experimental ...

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“…Temperature dependent absorption spectra of the excitons provide the energy shift of the band gap with temperature and also the temperature broadening of the excitonic resonance. These effects are in large part a result of electron-phonon interactions [28][29][30][31][32]. The energy shift of the exciton resonance with temperature for bulk MoS 2 , MoSe 2 , and WSe 2 obtained from the absorption spectra are shown in Fig.…”

mentioning

confidence: 99%

Optical Coherence in Atomic-Monolayer Transition-Metal Dichalcogenides Limited by Electron-Phonon Interactions

et al. 2016

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Temperature dependence of the shifts and broadenings of the critical points in GaAs

Cited by 137 publications

References 20 publications

Wannier interpolation of the electron-phonon matrix elements in polar semiconductors: Polar-optical coupling in GaAs

Wannier interpolation of the electron-phonon matrix elements in polar semiconductors: Polar-optical coupling in GaAs

High temperature mobility of CdTe

Optical Coherence in Atomic-Monolayer Transition-Metal Dichalcogenides Limited by Electron-Phonon Interactions

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