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Yamashita, Ken; Nakayama, Hiroshi; Nishino, Taneo

doi:10.1103/physrevb.53.15713

Cited by 21 publications

(14 citation statements)

References 24 publications

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“…1 In particular, the electronic band structures in long-range ordered ͑Al x Ga 1Ϫx ͒ y In 1Ϫy P alloys have been investigated by optical measurements and theoretical calculations. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] CuPt-type long-range ordering appears in ͑Al x Ga 1Ϫx ͒ y In 1Ϫy P alloys grown on GaAs͑001͒ substrates by metalorganic vapor-phase epitaxy ͑MOVPE͒. The ordered structure is equivalent to a monolayer superlattice alternating ͑Al x Ga 1Ϫx ͒and In-rich atomic planes along the ͓111͔ or ͓111͔ direction.…”

Section: Introductionmentioning

confidence: 99%

“…The energy of the ⌫(L) band in ordered ͑Al x Ga 1Ϫx ͒ 0.5 In 0.5 P alloys with xϽ0.6 is higher than that of the ⌫ band. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] By utilizing the BGR in ordered alloys, we can produce a new direct gap ͑Al x Ga 1Ϫx ͒ 0.5 In 0.5 P, when the energy of the reduced ⌫ band crosses the X band. 19 On the other hand, it is well known that epitaxially grown ordered alloys are comprised of many domains with varying values of the order parameter.…”

Section: Introductionmentioning

confidence: 99%

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Photoluminescence from metastable states in long-range ordered (Al0.5Ga0.5

1997

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We have investigated photoluminescence of long-range ordered ͑Al 0.5 Ga 0.5 ͒ 0.51 In 0.49 P grown by metalorganic vapor-phase epitaxy on GaAs͑001͒ and GaAs͑115͒A. Photoluminescence spectra were measured as functions of temperature and delay time. The fundamental edge luminescence from ͑Al 0.5 Ga 0.5 ͒ 0.51 In 0.49 P on GaAs͑001͒ shifts to the lower-energy side about 120 meV at 11 K due to the long-range ordering, relative to the luminescence from the ⌫ conduction-band valley in the disordered alloy. The ⌫ luminescence of ͑Al 0.5 Ga 0.5 ͒ 0.51 In 0.49 P appears at lower energy than the indirect luminescence from the X valley. These observations give clear evidence that the ordering causes the band gap to change from indirect to direct. In the temperature dependence of the photoluminescence ͑PL͒ peak energy, there are three regions divided by a local minimum and a local maximum. Below the temperature showing the local minimum, the temperature dependence of the PL intensity is characteristic of the localization of photoexcited carriers. The origin of the localization is the band-gap fluctuation. The temperature dependence of the PL intensity shows thermal activation between the temperatures showing the local minimum and the local maximum in the PL energy. The activation energy is proportional to the energy shift at the local minimum. In time-resolved PL measurements at low temperatures, we observed a delayed emission due to the electrons trapped at metastable states. The delayed component was only observed below 15 K and the delay time varies with temperature. ͓S0163-1829͑97͒12107-5͔

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photoluminescence from metastable states in long-range ordered (Al0.5Ga0.5

1997

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“…The maximum of VB and the minimum of CB are not at the same high symmetry point; one is at point V and the other is at point G, respectively. So IrN 2 crystal belongs to the type of indirect-gap semiconductor [29][30][31][32].…”

Section: Resultsmentioning

confidence: 99%

A DFT study on the electronic structure for iridium nitride under high pressure

Zhang

Cheng

2008

Struct Chem

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We present density functionary theory (DFT) calculations on the structural parameters and electronic structure for iridium nitride by using the generalized gradient approximation (GGA) and the Perdew-BurkeErnserhof (PBE) exchange-correlation functional. The lattice parameters and bulk modulus (B 0 ) for the ground state are obtained, and the energy band structure and electron densities of states (DOS) of IrN 2 are presented. It is found that IrN 2 has a very close indirect energy gap. There is a strong covalent bond between the two nearest N atoms. This gives rise to a very high elastic modulus of IrN 2 and reveals the quasimolecular nature of the N 2 in IrN 2 crystal. Lattice parameters, bulk modulus, and the electronic structure of IrN 2 under high pressure have also been investigated based on DFT. The compressibility along three cell vectors is very close to each other. The band gap increases a little with the pressure even when the pressure is up to 100 Gpa.

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“…The (Al x Ga 1Àx ) 0.5 In 0.5 P system exhibits CuPt-B type ordering of Al/Ga and In along the [1][2][3][4][5][6][7][8][9][10][11] or [-111] directions under certain growth conditions. 1 Ordering has been extensively studied in Ga 0.5 In 0.5 P and has been shown to lead to a reduction in band gap, valence band splitting, and an anisotropic matrix element, without a change in macroscopic composition or lattice-constant.…”

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confidence: 99%

“…2 This allows for the opportunity to create lattice-matched order-disorder heterostructures without critical thickness limitations of strained-layer epitaxy. Some potential benefits of using an ordered active layer with disordered barriers include greater carrier confinement, 3,4 increased energy separation from the indirect valley, 5,6 and even bandoffset adjustment. 7 Band-offset adjustment without band gap change is hypothetically possible by compensating for the ordering-induced band gap change with an increased Al/Ga ratio, although this has yet to be experimentally shown.…”

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confidence: 99%

Improved photoluminescence characteristics of order-disorder AlGaInP quantum wells at room and elevated temperatures

Mukherjee

Deotare

Fitzgerald

2015

Applied Physics Letters

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Photoluminescence decay dynamics in an InGaN/GaN/AlGaN single quantum wellA set of nominally undoped CuPt-B type ordered (Al x Ga 1Àx ) 0.5 In 0.5 P quantum-wells with disordered (Al 0.7 Ga 0.3 ) 0.5 In 0.5 P barriers were grown and characterized using transmission electron microscopy and photoluminescence spectroscopy. Such structures are potentially beneficial for light emitting devices due to the possibility of greater carrier confinement, reduced scattering into the indirect valleys, and band-offset adjustment beyond what is possible with strain and composition. Furthermore, the possibility of independently tuning the composition and the order-parameter of the quantum-well allows for the decoupling of the carrier confinement and the aluminum content and aids in the identification of carrier loss mechanisms. In this study, sharp order-disorder interfaces were achieved via the control of growth temperature between 650 C and 750 C using growth pauses. Improved high-temperature (400 K) photoluminescence intensity was obtained from quantum-wells with ordered Ga 0.5 In 0.5 P as compared to disordered Ga 0.5 In 0.5 P due to greater confinement. Additionally, in the ordered samples with a higher Al/Ga ratio to counter the band-gap reduction, the photoluminescence intensity at high temperature was as bright as that from conventional disordered heterostructures and had slightly improved wavelength stability. Room-temperature time-resolved luminescence measurements indicated a longer radiative lifetime in the ordered quantum-well with reduced scattering into the barrier. These results show that in samples of good material quality, the property controlling the luminescence intensity is the carrier confinement and not the presence of ordering or the aluminum content. V C 2015 AIP Publishing LLC. [http://dx.

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Direct optical transitions in indirect-gap (Al0.5Ga0.5

Cited by 21 publications

References 24 publications

Photoluminescence from metastable states in long-range ordered (Al0.5Ga0.5

Photoluminescence from metastable states in long-range ordered (Al0.5Ga0.5

A DFT study on the electronic structure for iridium nitride under high pressure

Improved photoluminescence characteristics of order-disorder AlGaInP quantum wells at room and elevated temperatures

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