Raman study of longitudinal optical phonon-plasmon coupling and disorder effects in heavily Be-doped GaAs

Mlayah, Adnen; Carles, R.; Landa, Georges; Bedel, E.; Muñoz‐Yagüe, A.

doi:10.1063/1.348957

Cited by 69 publications

(47 citation statements)

References 25 publications

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“…Similar weakly damped LOPC modes have also been reported for other III-V semiconductors such as GaSb 18 , InN 19 , InP 20 , InAs 21 , and GaN 22 . For p-type GaAs, the LOPC mode appears within the reststrahlen gap between ν LO and ν TO , because of the fast plasma damping (γ h > 2πν LO ) caused by the hole momentum scattering [14][15][16][17] . In other p-type III-V semiconductors [23][24][25][26] , however, no such heavily damped LOPC modes have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…In polar semiconductors like group III-V, Coulomb interaction between the collective oscillation of the electric charges (plasma) and the lattice polarization of the longitudinal optical (LO) phonons renormalizes their frequencies to give rise to LO phonon-plasmon coupled (LOPC) modes 10,11 . The LOPC modes have been studied by Raman scattering especially for GaAs [12][13][14][15][16][17] . Due to the band-dependent damping rates for electron and hole plasmas, the LOPC modes in n-and p-redtype semiconductors behave very differently.…”

Section: Introductionmentioning

confidence: 99%

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Dynamically coupled plasmon-phonon modes in GaP: An indirect-gap polar semiconductor

et al. 2015

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The ultrafast coupling dynamics of coherent optical phonons and the photoexcited electron-hole plasma in the indirect gap semiconductor GaP are investigated by experiment and theory. For below-gap excitation and probing by 800-nm light, only the bare longitudinal optical (LO) phonons are observed. For above-gap excitation with 400-nm light, the photoexcitation creates a high density, nonequilibrium e−h plasma, which introduces an additional, faster decaying oscillation due to an LO phonon-plasmon coupled (LOPC) mode. The LOPC mode frequency exhibits very similar behavior for both n-and p-doped GaP, downshifting from the LO to the transverse optical (TO) phonon frequency limits with increasing photoexcited carrier density. We assign the LOPC mode to the LO phonons coupled with the photoexcited multi-component plasma. For the 400-nm excitation, the majority of the photoexcited electrons are scattered from Γ valley into the satellite X valley, while the light and spin-split holes are scattered into the heavy hole band, within 30 fs. The resulting mixed plasma is strongly damped, leading to the LOPC frequency appearing in the reststrahlen gap. Due to the large effective masses of the X electrons and heavy holes, the coupled mode appears most distinctly at carrier densities 5 × 10 18 cm −3 . We perform theoretical calculations of the nuclear motions and the electronic polarizations following an excitation with an ultrashort optical pulse to obtain the transient reflectivity responses of the coupled modes. We find that, while the longitudinal diffusion of photoexcited carriers is insignificant, the lateral inhomogeneity of the photoexcited carriers due to the laser intensity profile should be taken into account to reproduce the major features of the observed coupled mode dynamics.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamically coupled plasmon-phonon modes in GaP: An indirect-gap polar semiconductor

et al. 2015

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“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23] In contrast, only a few investigations of p-type GaSb have been reported. [24][25][26][27][28] Of these reports, one involves the same epilayers investigated here: zincdoped in the range of 1.92 x 10 17 cm -3 to 6.38 x 10 18 cm -3 , as determined from single magnetic field Hall effect measurements.…”

Section: Introductionmentioning

confidence: 99%

Raman Spectroscopy Determination of Hole Concentration in p-Type GaSb

WS¹

2007

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Room temperature p-type GaSb bulk coupled mode spectra were measured as a function of hole concentration. These spectra were obtained using an optical system based on 752.55 nm excitation in order to obtain more sensitivity to bulk GaSb coupled mode scattering than possible with visible wavelength excitation-based systems. A relatively simple spectral model for the electronic contribution to the dielectric function was evaluated for determination of hole concentration from the bulk coupled mode spectra. Optically-derived values for hole concentration were determined by minimizing the sum of the residuals squared between an experimental and simulated spectrum as a function of total hole concentration and a plasmon damping parameter. Hole concentrations obtained from the Raman spectroscopic measurements deviated from the values determined from single field Hall effect measurements that were corrected to account for two band conduction by ≈20% to ≈65%. These deviations were attributed to the limitations of the spectral model employed and uncertainties in GaSb materials properties.

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“…5,6 Many Raman scattering measurements performed in n-and p-type materials have put the emphasis on the longitudinal vibration of the carrier plasma which couples with the LO phonon via the macroscopic electric field to form a phononlike LO phonon-plasmon coupling (LOPC) mode. Such a mechanism has been studied in p-type GaAs as a function of different carbon, 7 silicon, 8 beryllium, 9,10 and zinc 11 doping levels. These previous reports have shown that the relative integrated areas of the LO phonon bands ͑I LO ͒ and the LOPC bands ͑I LOPC ͒ can directly be connected to the free carrier concentration located in the Raman probed volume, thus allowing one to estimate the depletion layer depth in the vicinity of the sample surface.…”

Section: Introductionmentioning

confidence: 99%

Raman study of As outgassing and damage induced by ion implantation in Zn-doped GaAs

Barba

Aimez

Beauvais

et al. 2004

Journal of Applied Physics

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Room temperature micro-Raman investigations of LO phonon and LO phonon-plasmon coupling is used to study the As outgassing mechanism and the disordering effects induced by ion implantation in Zn-doped GaAs with nominal doping level p =7ϫ 10 18 cm −3 . The relative intensity of these two peaks is measured right after rapid vacuum thermal annealings (RVTA) between 200 and 450°C, or after ion implantations carried out at energies of 40 keV with P + , and at 90 and 170 keV with As + . These intensities provide information regarding the Schottky barrier formation near the sample surface. Namely, the Raman signature of the depletion layer formation resulting from As desorption is clearly observed in samples submitted to RVTA above 300°C, and the depletion layer depths measured in ion implanted GaAs: Zn are consistent with the damage profiles obtained through Monte Carlo simulations. Ion channeling effects, maximized for a tilt angle set to 45°during implantation, are also investigated. These results show that the Raman spectroscopy is a versatile tool to study the defects induced by postgrowth processes in multilayered heterostructures, with probing range of about 100 nm in GaAs-based materials.

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Raman study of longitudinal optical phonon-plasmon coupling and disorder effects in heavily Be-doped GaAs

Cited by 69 publications

References 25 publications

Dynamically coupled plasmon-phonon modes in GaP: An indirect-gap polar semiconductor

Dynamically coupled plasmon-phonon modes in GaP: An indirect-gap polar semiconductor

Raman Spectroscopy Determination of Hole Concentration in p-Type GaSb

Raman study of As outgassing and damage induced by ion implantation in Zn-doped GaAs

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