Infrared reflectance studies of bulk and epitaxial-film <i>n</i>-type GaAs

Holm, R. T.; Gibson, John W.; Palik, E. D.

doi:10.1063/1.323322

Cited by 135 publications

(56 citation statements)

References 48 publications

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“…It is much broader than the electron-plasma reflectivity minimum seen in n-type GaAs. [22][23][24] The phonon band in GaAs:C is also affected by carrier concentration. In samples ͑a͒-͑d͒, with hole concentrations below 10 19 cm Ϫ3 , the phonon band is sharp and strong while the plasmon minimum is quite weak.…”

Section: Infrared Reflectivity: Hole Plasmonsmentioning

confidence: 99%

“…The first term in Eq. ͑2͒ is equivalent to the reflectivity of a thin absorbing film on an opaque substrate, 22,27,28,32 and the second term is derived from the sum of a geometric series of multiple reflections across the substrate. The quantity given by Eq.…”

Section: ͑8͒mentioning

confidence: 99%

“…The Drude model provides the simplest approximation for the contribution, to the optical dielectric function, of the free-carrier plasma. It has been successfully applied to n-type GaAs, [22][23][24] in which electrons occupy a single conduction band, using a single plasmon frequency and damping constant. For p-type material, the free carriers are holes which populate two different bands, the heavy-hole and light-hole bands, to different extents in k space.…”

Section: Introductionmentioning

confidence: 99%

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Infrared studies of hole-plasmon excitations in heavily-doped p-type MBE-grown GaAs:C

Songprakob

Zallen²,

Liu³

et al. 2000

Phys. Rev. B

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Infrared reflectivity measurements ͑200-5000 cm Ϫ1 ) and transmittance measurements ͑500-5000 cm Ϫ1 )have been carried out on heavily-doped GaAs:C films grown by molecular-beam epitaxy. With increasing carbon concentration, a broad reflectivity minimum develops in the 1000-3000 cm Ϫ1 region and the onephonon band near 270 cm Ϫ1 rides on a progressively increasing high-reflectivity background. An effectiveplasmon/one-phonon dielectric function with only two free parameters ͑plasma frequency p and damping constant ␥) gives a good description of the main features of both the reflectivity and transmittance spectra. The dependence of p 2 on hole concentration p is linear; at pϭ1.4ϫ10 20 cm Ϫ3 , p is 2150 cm Ϫ1 . At each doping, the damping constant ␥ is large and corresponds to an infrared hole mobility that is about half the Hall mobility. Secondary-ion mass spectroscopy and localized-vibrational-mode measurements indicate that the Hall-derived p is close to the carbon concentration and that the Hall factor is close to unity, so that the Hall mobility provides a good estimate of actual dc mobility. The observed dichotomy between the dc and infrared mobilities is real, not a statistical-averaging artifact. The explanation of the small infrared mobility resides in the influence of intervalence-band absorption on the effective-plasmon damping, which operationally determines that mobility. This is revealed by a comparison of the infrared absorption results to Braunstein's low-p p-GaAs spectra and to a k"p calculation extending Kane's theory to our high dopings. For n-GaAs, which lacks infrared interband absorption, the dc and infrared mobilities do not differ.

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Section: Infrared Reflectivity: Hole Plasmonsmentioning

confidence: 99%

Section: ͑8͒mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Infrared studies of hole-plasmon excitations in heavily-doped p-type MBE-grown GaAs:C

Songprakob

Zallen²,

Liu³

et al. 2000

Phys. Rev. B

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“…We model the uniaxially anisotropic contributions by combining a Lorentz oscillator for the one-phonon absorption with the Drude equation. 24,25 To this model, we add the weaker twophonon summation bands, resulting in …”

Section: Sic Optical Response Modelmentioning

confidence: 99%

“…These have been previously measured. 14,25 For 6H SiC, modes parallel to the c axis ͑extraordinary optical response͒ are TOʈ ϭ788 cm Ϫ1 and LOʈ ϭ964 cm Ϫ1 , modes perpendicular to the c axis ͑ordinary optical response͒ are TOЌ ϭ797 cm Ϫ1 and LOЌ ϭ970 cm…”

Section: Sic Optical Response Modelmentioning

confidence: 99%

Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry

et al. 1999

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Wetteroth, T.; Wilson, S. R.; and Powell, Adrian R., "Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry" (1999 Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry We have measured the dielectric function of bulk nitrogen-doped 4H and 6H SiC substrates from 700 to 4000 cm Ϫ1 using Fourier-transform infrared spectroscopic ellipsometry. Photon absorption by transverse optical phonons produces a strong reststrahlen band between 797 and 1000 cm Ϫ1 with the effects of phonon anisotropy being observed in the region of the longitudinal phonon energy ͑960 to 100 cm Ϫ1 ͒. The shape of this band is influenced by plasma oscillations of free electrons, which we describe with a classical Drude equation. For the 6H-SiC samples, we modify the Drude equation to account for the strong effective mass anisotropy. Detailed numerical regression analysis yields the free-electron concentrations, which range from 7ϫ10 17 to 10 19 cm Ϫ3 , in good agreement with electrical and secondary ion mass spectrometry measurements.Finally, we observe the Berreman effect near the longitudinal optical phonon energy in nϪ/nϩ homoepitaxial 4H SiC and hydrogen implanted samples, and we are able to determine the thickness of these surface layers.

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Simultaneous Control of Spectral And Directional Emissivity with Gradient Epsilon‐Near‐Zero InAs Photonic Structures

2023

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Controlling both the spectral bandwidth and directionality of emitted thermal radiation is a fundamental challenge in contemporary photonics. Recent work has shown that materials with a spatial gradient in the frequency range of their epsilon‐near‐zero (ENZ) response can support broad spectrum directionality in their emissivity, enabling high total radiance to specific angles of incidence. However, this capability is limited spectrally and directionally by the availability of materials with phonon‐polariton resonances over long‐wave infrared wavelengths. Here, an approach is designed and experimentally demonstrated using doped III–V semiconductors that can simultaneously tailor spectral peak, bandwidth, and directionality of infrared emissivity. InAs‐based gradient ENZ photonic structures that exhibit broadband directional emission with varying spectral bandwidths and directional ranges as a function of their doping concentration profile and thickness are epitaxially grown and characterized. Due to its easy‐to‐fabricate geometry, it is believed that this approach provides a versatile photonic platform to dynamically control broadband spectral and directional emissivity for a range of emerging applications in heat transfer and infrared sensing.

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Infrared reflectance studies of bulk and epitaxial-film n-type GaAs

Cited by 135 publications

References 48 publications

Infrared studies of hole-plasmon excitations in heavily-doped p-type MBE-grown GaAs:C

Infrared studies of hole-plasmon excitations in heavily-doped p-type MBE-grown GaAs:C

Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry

Simultaneous Control of Spectral And Directional Emissivity with Gradient Epsilon‐Near‐Zero InAs Photonic Structures

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