Raman-scattering spectra of coupled LO-phonon–hole-plasmon modes in<i>p</i>-type GaAs

Fukasawa, Ryoichi; Perkowitz, Sidney

doi:10.1103/physrevb.50.14119

Cited by 83 publications

(86 citation statements)

References 24 publications

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“…Eq. (7) reproduced well the carrier density dependent frequency by assuming a large plasmon damping, γ > 9 THz 20,21 . At hole densities below 2 × 10 18 cm −3 , the LO-hole coupled mode was not observed as a distinct mode either in Raman scattering 20 or as a coherent oscillation in transient reflectivity 7,8 , because its frequency is very close to Ω LO .…”

Section: Lopc Mode In the Depletion Layermentioning

confidence: 58%

“…For p-doped GaAs, by contrast, the frequency is reproduced by the overdamped (γ > Ω LO ) solution of eq. (7), which gives a phonon-like coupled mode with a frequency between Ω LO and Ω T O , in addition to an overdamped plasmon mode, which is generally too broad to appear as a distinct spectroscopic feature 20,21 . Because of the formation of the depletion or accumulation layer at the surface, the LOPC mode properties can be strongly depth-dependent in the surface region through the free carrier concentration.…”

Section: B Lopc Modes In Polar Compound Semiconductorsmentioning

confidence: 99%

“…The frequencies of the LOPC modes are obtained by solving the equation for the frequency-dependent dielectric response of the lattice and electrons 20,21 :…”

Section: B Lopc Modes In Polar Compound Semiconductorsmentioning

confidence: 99%

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Allowed and forbidden Raman scattering mechanisms for detection of coherent LO phonon and plasmon-coupled modes in GaAs

2011

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Detection mechanisms of coherent phonons in variously doped GaAs are investigated by transient reflectivity method with photoexcitation near the E0 gap and probe near either the E0 or E1 gaps. By varying the probe light polarization angle, the coherent amplitudes of both the LO phonon and the LO phonon-plasmon coupled (LOPC) modes show evidence for an interference between their anisotropic and isotropic dielectric response components. We attribute the anisotropic and isotropic components to the reflectivity modulation by lattice and electronic polarizations via dipole-allowed and dipole-forbidden Raman scattering processes. The forbidden processes are resonantly enhanced at the E0 and E1 critical points due to the relaxation of momentum conservation and the strong built-in electric field near the surface. The relative contribution of the anisotropic and isotropic components depends on the modes (LO or LOPC) as well as the probe wavelength (E0 or E1), because of the different Raman scattering mechanisms involved. Reflectivity measurements with the near ultraviolet light, which is used to probe the E1 gap, also enable highly surface sensitive detection of ultrafast LO phonon-plasmon dynamics, which is strongly depth-dependent in the depletion layer of n-doped GaAs.

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Section: Lopc Mode In the Depletion Layermentioning

confidence: 58%

Section: B Lopc Modes In Polar Compound Semiconductorsmentioning

confidence: 99%

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Allowed and forbidden Raman scattering mechanisms for detection of coherent LO phonon and plasmon-coupled modes in GaAs

2011

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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-scattering spectra of coupled LO-phonon–hole-plasmon modes inp-type GaAs

Cited by 83 publications

References 24 publications

Allowed and forbidden Raman scattering mechanisms for detection of coherent LO phonon and plasmon-coupled modes in GaAs

Allowed and forbidden Raman scattering mechanisms for detection of coherent LO phonon and plasmon-coupled modes in GaAs

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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