Room temperature electroluminescence in the midinfrared near 4 m is reported from GaInAsSbP light emitting diodes grown on GaSb by liquid phase epitaxy. Comparison of the electro-and photoluminescence revealed that light is generated on the p side of the diode. The energy shift ͑24 meV͒ is consistent with band gap narrowing and recombination via band tail states due to the Zn doping ͑1 ϫ 10 18 cm −3 ͒ in the p layer of the structure. The temperature dependent behavior of the luminescence and the improved emission intensity was attributed to recombination from localized states arising from electrostatic potential fluctuations due to compositional inhomogeneities in these alloys. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2741147͔The realization of high emittance light emitting diodes ͑LEDs͒ and lasers for the midinfrared ͑2-5 m͒ spectral range, which can work efficiently at room temperature, is hampered by competing nonradiative Auger recombination and intervalence band absorption ͑IVBA͒. 1 This leads to poor internal efficiency in LEDs and high threshold currents in diode lasers. If suitable optoelectronic components could be made available one can envisage a wide variety of applications, including chemical process control, environmental monitoring of atmospheric pollution, and free space optical communications. One promising approach is to use the GaInAsPSb pentanary alloys because for a given value of the band gap ͑or lattice constant͒ properties such as the refractive index, spin-orbit valence band splitting ͑⌬ so ͒, or thermal expansion coefficient can be independently varied. 2,3 This offers a different approach to control optical confinement, carrier leakage, IVBA, and Auger recombination. However, although GaInAsPSb alloys have been grown, there has been very little work in this area. 4,5 Luminescence emission properties of broken gap GaInAsSbP / InAs isotype heterostructures and prototype light emitting diodes and photodiodes at short wavelengths ͑ Ͻ4 m͒ have been reported for alloys grown by liquid phase epitaxy ͑LPE͒ lattice matched onto InAs. 6,7 Recently, AlGaInAsSb alloys grown by molecular beam epitaxy have been effectively used as the barrier layers in room temperature midinfrared quantum well lasers. 8 In this letter the epitaxial growth of GaInAsPSb/ GaSb p-i-n structures from the liquid phase and a study of their electroluminescence properties are presented.Epitaxial growth of Ga 1−x In x As y P z Sb l-y-z single epilayers as well as p-i-n homostructures in which p-type layers were doped with Zn ͑1 ϫ 10 18 cm −3 ͒ and n-type layers were doped with Te ͑4 ϫ 10 17 cm −3 ͒ was carried out from antimony-rich melts onto Ge doped p-type GaSb ͑100͒ substrates. The use of antimony as the solvent for LPE growth of GaSb-related alloys has some advantages 9,10 compared with the more conventional techniques based on the low melting point metals, using In or Ga as solvents, namely, ͑1͒ Growth from Sb solution decreases the concentration of stoichiometric defects such as V Ga +Ga Sb , ͑2͒ etchback ...

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Room temperature photoluminescence is reported from GaInAsSbP pentanary alloys grown by liquid phase epitaxy on GaSb. The epitaxial layers exhibited emission in the midinfrared between 3 and 4 m. Investigation of the structural and photoluminescence properties revealed localization effects associated with potential fluctuations in the pentanary alloy arising from compositional modulation. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2768892͔Continuing interest in the development of III-V materials for use in midinfrared ͑2-5 m͒ light sources and detectors is driven by the extensive range of potential applications in this spectral region, including environmental gas monitoring, noninvasive medical diagnosis, tunable IR spectroscopy, and free space optical communications. 1 The pentanary alloys, such as GaInAsSbP, offer some useful advantages to the device engineer by making available an additional degree of freedom. 2,3 For a given value of the band gap or lattice constant, properties, such as the refractive index, spin-orbit valence band splitting, band offsets, etc., can be independently varied. This could enable control of optical confinement, carrier leakage, intervalence band absorption, and Auger recombination. However, there have been very few reports on the growth and the luminescence properties of GaInAsSbP pentanary alloys. 3,4 Recently, however, AlGaInAsSb alloys have been grown by molecular beam epitaxy and effectively used as the barrier layers in room temperature midinfrared quantum well lasers. 5 Here we report on the liquid phase epitaxial growth of GaInAsSbP pentanary alloys and demonstrate room temperature photoluminescence ͑PL͒ in the 3 -4 m spectral range.Epitaxial growth of pentanary GaInAsPSb single epilayers was carried out from antimony-rich melts onto Ge doped p-type GaSb ͑100͒ substrates. Growth melts were prepared from 6N Sb and 7N In pure metals, while the sources of Ga, As, and P were undoped polycrystalline GaSb, InAs, and InP binary compounds. The use of antimony as the solvent for liquid phase epitaxy ͑LPE͒ growth of GaSb-related alloys has some advantages because it avoids substrate erosion and reduces the formation of Sb vacancies. 6-8 Growth was implemented from supercooled melts at temperatures within the interval of 585-600°C. In each case before the deposition of the GaInAsPSb pentanary alloy an undoped GaSb p-type buffer layer was grown on the substrate. Structural characterization of the resulting epitaxial layers was done using phase contrast Nomarski microscopy, field emission electron microscopy, and high resolution x-ray diffraction. Subsequent optical investigation of the GaInAsSbP structures included PL spectroscopy using an Ar + ion laser ͑514 nm͒ which produced an excitation power density of 20 W cm −2 on the sample. Temperature dependent PL measurements over the range of 4 -300 K were carried out using conventional lock-in techniques. Additional measurements were made with a Bruker IFS 66/S Fourier transform infrared spectrometer and a 77 K InSb photodiod...

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GaInAsPSb is a new narrow gap semiconductor material which is suitable for the fabrication of semiconductor light sources for the mid‐infrared spectral range. Photoluminescence emission spectra from GaInAsPSb grown by LPE and lattice‐matched onto GaSb substrates were investigated. Homojunction p–i–n light‐emitting diodes in this pentenary alloy were fabricated and electroluminescence peaking near 4.0 μm at room temperature was observed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)