Photoluminescence and excitation-photoluminescence study of spontaneous ordering in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">GaInP</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Horner, G.S.; Mascarenhas, A.; Alonso, R.G.; Froyen, Sverre; Bertness, K. A.; Olson, J. M.

doi:10.1103/physrevb.49.1727

Cited by 46 publications

(24 citation statements)

References 16 publications

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“…Similar behavior has also been observed in MOCVD grown In x Ga 1Ϫx P alloys 3 and it was ascribed to long range ordering. Stokes shifts of 17 meV have been previously reported 17 in disordered In x Ga 1Ϫx P samples as due to alloy disorder phenomena.…”

Section: Figsupporting

confidence: 78%

“…9 CuPt-like ordering induces specific modifications in the band structure of the In x Ga 1Ϫx P layers, and the energy redshift of the photoluminescence ͑PL͒ line is currently used as a measure of the degree of ordering. 2,3 To our knowledge, the effect of compositional modulation, promoted by spinodal decomposition, on the optical properties of disordered layers have not been studied.…”

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confidence: 99%

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Optical characterization of disordered InxGa1−xP alloys

González¹,

González²,

Dotor³

et al. 1998

Applied Physics Letters

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We present results on the optical characterization of In x Ga 1Ϫx P layers grown by atomic layer molecular beam epitaxy on GaAs ͑001͒ substrates at a growth temperature of 420°C. Our results show that the optical characteristics of these layers, which do not show ordering effects, are strongly dependent on surface stoichiometry during growth. In this way, we can obtain either highly homogeneous alloys with a predictable band-gap energy or layers with optical properties indicative of spatial localization effects, like an anomalous behavior of photoluminescence peak energy with temperature and a large shift between the emission energy and absorption edge. © 1998 American Institute of Physics. ͓S0003-6951͑98͒01920-2͔The In x Ga 1Ϫx P alloy lattice matched to GaAs (x ϭ0.48) has enormous interest for its application in visible light emitters and as an alternative to AlGaAs in GaAs based devices. In particular, In x Ga 1Ϫx P/GaAs based tandem solar cells have reached the highest efficiency achieved at present. 1For device applications it is obviously necessary to know the band-gap energy of the alloy. However, it has been shown 2,3 that formation during growth of ordered domains with CuPt structure decreases the effective band-gap energy and broadens the absorption edge.This alloy exhibits other structural features, which are also growth dependent and are related to the existence of a miscibility gap in the range of growth temperatures used in some epitaxial techniques. 4 This means that In x Ga 1Ϫx P is thermodynamically unstable against separation into two phases of different compositions. In fact there is experimental evidence of some effects related to spinodal decomposition in layers grown by the usual nonequilibrium epitaxial techniques. For example, it is now well established that In x Ga 1Ϫx P layers show quasiperiodic variations in composition over ranges from a few nm to hundreds of nm.2,5-8 This modulated phase separation results in lattice strains which produce contrasts in transmission electron microscopy ͑TEM͒ images. CuPt-like ordering induces specific modifications in the band structure of the In x Ga 1Ϫx P layers, and the energy redshift of the photoluminescence ͑PL͒ line is currently used as a measure of the degree of ordering.2,3 To our knowledge, the effect of compositional modulation, promoted by spinodal decomposition, on the optical properties of disordered layers have not been studied.In this letter we present results on optical behavior of disordered In x Ga 1Ϫx P layers grown at low substrate temperature (T s Ϸ420°C) by atomic layer molecular beam epitaxy ͑ALMBE͒. Structural characterization of the samples was made by high resolution x-ray diffraction ͑HRXRD͒ and Raman spectroscopy, and results will be shown using PL and photoluminescence excitation ͑PLE͒.According to our previous work, 10 the In x Ga 1Ϫx P layers can show either a fine speckle structure with a size in the range 10-20 nm, or superposed to this, a long wavelength contrast (Ϸ80 nm). These features have been related to alloy clu...

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confidence: 78%

mentioning

confidence: 99%

Optical characterization of disordered InxGa1−xP alloys

González¹,

González²,

Dotor³

et al. 1998

Applied Physics Letters

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“…3,4,6 Such ordering both lowers the band-gap energy and splits the quadruply degenerate valence band states. These ordering-induced electronic structure changes have been well established by photoluminescence ͑PL͒, 2,6 photoluminescence excitation, 7,8 and polarized piezomodulation 5 spectroscopies as well as more recent exciton absorption bleaching measurements. 9 First-principles and perturbation based electronic structure calculations agree well with these experiments.…”

Section: Introductionmentioning

confidence: 76%

Electroreflectance measurements of electric fields in ordered GaInP2

Perkins

Zhang

Geisz

et al. 1998

Journal of Applied Physics

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Ordered Ga0.52In0.48P alloys (GaInP2 for simplicity) grown on miscut [001] GaAs resemble monolayer superlattices with alternating Ga- and In-rich layers along either the [1̄11] or [11̄1] directions. Recent calculations suggest that, in fully ordered GaInP2, an intrinsic ordering-induced electric field of order 1600 kV/cm should exist. In partially ordered samples, as can actually be grown, the expected field is reduced to 400 kV/cm. For such a strong internal electric field, clear Franz–Keldysh Oscillations (FKOs) would be expected in an electroreflectance measurement. We report electroreflectance measurements of ordered GaInP2 layers measured at T=100 K. For all samples measured, no FKOs are observed in the absence of an additional external dc bias voltage. At the lowest bias voltages for which FKOs are seen, the internal electric field in the GaInP2 layer, determined from the FKOs, is ∼60 kV/cm along the [001] direction corresponding to ∼100 kV/cm along the ordering direction. Hence, we conclude that, at least in the organometallic vapor phase epitaxy grown samples studied here, any net macroscopic internal electric field in the GaInP2 layer is less than ∼100 kV/cm along the ordering direction.

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“…[1][2][3][4][5][6][7][8][9][10] The long-range ordering of the column III sublattice appears in Ga 0.5 In 0.5 P epitaxial films grown on GaAs ͑001͒ by organometallic vapor-phase epitaxy ͑OM-VPE͒. The epitaxial alloys consist of two ordered phases that show the CuPt-like ordering along the ͓111͔ and ͓111͔, i.e., ͓111͔ and ͓111͔ monolayer superlattices ͑MSLs͒.…”

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“…[8][9][10] The PLE spectra show anisotropic optical absorptions originated from the valence-band splitting. For applications of such anisotropic properties near the band gap into optoelectronic devices, it is important to investigate properties of photocurrent ͑PC͒ responses in ordered Ga 0.5 In 0.5 P. The PC response is not only a function of absorption coefficient, but also of electronic structure of the junction and transport properties of photoexcited carriers.…”

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Photocurrent polarization in long-range ordered Ga0.5In0.5P

Fujiwara

Nakayama

Nishino

1995

Applied Physics Letters

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Photocurrent polarization properties near the band gap of long-range ordered Ga0.5In0.5P have been investigated. The linearly polarized PC spectra of the ordered Ga0.5In0.5P show an absorption anisotropy for the [110] and [11̄0] directions together with a large band-gap reduction. The anistotropy in the PC spectra is due to a crystal-field splitting at the valence-band maximum in ordered Ga0.5In0.5P. The PC edge of the [110] polarization is lower at about 10 meV than one of the [11̄0]. The polarization spectra defined by (I110−I11̄0)/(I110+I11̄0), where I110 and I11̄0 are the PC signal intensities measured at the [110] and [11̄0], respectively, show a single broad peak. The maximum polarization reaches about 50% at the energy of the transition between Γ6c and Γ4v, Γ5v. With increased sample temperature, the polarization maximum shifts to the lower energy side according to the change of the Γ6c-Γ4v,Γ5v transition energy. Even at room temperature, a clear polarization signal was observed.

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Photoluminescence and excitation-photoluminescence study of spontaneous ordering inGaInP2

Cited by 46 publications

References 16 publications

Optical characterization of disordered InxGa1−xP alloys

Optical characterization of disordered InxGa1−xP alloys

Electroreflectance measurements of electric fields in ordered GaInP2

Photocurrent polarization in long-range ordered Ga0.5In0.5P

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