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The n+-InAs/n0-InAs1 –ySby/p-InAsSbP heterostructures with asymmetric band offsets at the heteroboundaries of the active region have been grown by vapor-phase epitaxy from organometallic compounds on InAs substrates. The forward branch of the current–voltage characteristics of the obtained heterostructures at low temperatures has segments with the tunneling conduction. The energy-band diagram of the double InAs/InAs1 –ySby/InAsSbP heterostructure is calculated in the range of compositions (y < 0.2) of the narrow-gap active region. The InAs1 –ySby/InAsSbP heterojunction is shown to be a II type heterojunction in this composition range. The electroluminescence observed in the experiment for the n+-InAs/n0-InAs1 ‒ySby/p-InAsSbP heterostructures with the active region in compositions y > 0.14 is due to interface radiative transitions with participation of localized hole states at the II type heteroboundary. [ABSTRACT FROM AUTHOR]

Electroluminescence bistability is observed in a typ-II P-AlGaAsSb/p-InGaAsSb/ N-AlGaAsSbheterostructure with lightly doped cladding layers and a narrow-gap active region (the width of the band gap is E[sub g]= 326 meV at the temperature T = 77 K). A currentcontrolled negative differential resistance is observed in the forward branch of the currentvoltage characteristic. Strong narrowband electroluminescence (half-width ∼ 7 - 10 meV) is observed at the end of the negative differential resistance interval, where the photon energy at the radiation maximum exceeds the width of the band gap of the narrow-gap material by 50 meV. This phenomenon is attributed to the tunneling injection and indirect radiative recombination of carriers localized at the AlGaAsSb/InGaAsSb heterojunction. As the voltage is increased, radiative transitions in the bulk of the active region begin to provide the main contribution, and the radiation maximum jumps to the long-wavelength end. Tunneling injection structures of this kind can be used to construct highly efficient current-controlled lightemitting diodes. [ABSTRACT FROM AUTHOR]

Intense mid-infrared (λ∼2 μm) room temperature electroluminescence from metal organic vapor phase epitaxy (MOVPE) grown type-I single AlSb/InAsSb/AlSb quantum wells (QWs) is reported. The spectral position of the electroluminescent peaks is in good agreement with k·p envelope function calculation in the frame of four-band Kane’s model taking into account the intermixing of s and p states in the deep quantum well. A four times increase of the emission intensity with temperature increasing from 77 to 300 K can be explained by highly efficient radiative recombination of the electrons injected into the narrow AlSb/InAsSb/AlSb QW due to its specific design, leading to Auger process suppression. [ABSTRACT FROM AUTHOR]

We report on the electroluminescent and I–V characteristics of the n-InAs/n-InAsSb/p-InAsSbP heterostructure grown by metalorganic vapor-phase epitaxy. In the spectral range of 0.23–0.29 eV, the high-intensity electroluminescence at a temperature of T = 77 K has been observed. The position of the maximum of the main emission band ( ~ 0.24 eV) has shown a noticeable blue shift with increasing forward bias. Based on the investigations, a conclusion about the existence of a type-II staggered heterojunction at the InAs0.84Sb0.16/InAs0.32Sb0.28P0.40 heterointerface has been drawn, which is confirmed by the calculated energy band diagram. [ABSTRACT FROM AUTHOR]

The electroluminescent characteristics of the InAs/InAs1–ySby/InAsSbP asymmetric light-emitting diode heterostructures with high InSb mole fraction in the active region (y > 0.09) in the temperature range 4.2–300 K have been studied. Stimulated emission was achieved in the wavelength range 4.1–4.2 μm at low temperatures (T < 30 K). It was found that the electroluminescence spectra were formed as a result of the superposition of contributions from different channels of radiative recombination of charge carriers near the type II heterointerface. The effect of the quality of the type II InAsSb/InAsSbP heterojunction on the radiative interface transitions with an increase in the content of InSb in the ternary solid solution is considered. [ABSTRACT FROM AUTHOR]

Single heterostructures of type II n+-InAs/n0-InAs0.59Sb0.16P0.25, based on an intentionally undoped epitaxial layer with an electronic type of conductivity are obtained by metalorganic vapor phase epitaxy (MOVPE). In the heterostructure, a transition layer of modulated composition is formed near the heterointerface in the bulk of the quaternary solid solution. The existence of a radiative recombination channel due to the presence of localized hole states in quantum wells formed in the transition layer near the heterointerface is shown. It is demonstrated that the maximum of the intensity of the electroluminescence spectrum of the heterostructure under study is rearranged when a forward external bias is applied. The results of this study can be used in the development of tunable light-emitting diodes operating in the midinfrared range of 2-4 μm. [ABSTRACT FROM AUTHOR]

Luminescent characteristics of asymmetric p-InAs/AlSb/InAsSb/AlSb/ p-GaSb type II heterostructures with deep quantum wells at the heterointerface are studied. The heterostructures were grown by metalorganic vapor phase epitaxy. Intense positive and negative luminescence was observed in the range of photon energies of 0.3–0.4 eV with a forward and reverse bias, respectively. Dependences of the spectra and intensities for positive and negative luminescence on the pumping current and on the temperature are studied in the range of 77–380 K. It is established that, at a temperature higher than 75°C, intensity of negative luminescence surpasses that of positive luminescence by 60%. The suggested heterostructures can be used as lightemitting diodes (photodiodes) with switched positive and negative luminescence in the mid-IR spectral range of 3–4 μm. [ABSTRACT FROM AUTHOR]

A study of the electroluminescence of asymmetric InAs/InAs1 – ySby/InAsSbP light-emitting diode heterostructures with a molar fraction of InSb in the ternary solid solution in the active region y = 0.15 and y = 0.16 in the temperature range 4.2–300 K is reported. It is found on the basis of experimental data that a staggered type-II heterojunction is formed at the InAs1 – ySby/InAs0.41Sb0.28P0.40 heterointerface. It is shown that interfacial radiative transitions at the type-II heterointerface make a dominant contribution in the temperature range of 4.2–180 K. This enables minimization of the temperature dependence of the operating wavelength of a light-emitting diode. [ABSTRACT FROM AUTHOR]

The design and technology for the fabrication of an asymmetric stepped InAs/InAs1 –ySby/InAsSbP heterostructure with an ultimate InSb content (up to y = 0.17) in the narrow-gap active region by vapor-phase epitaxy from metal-organic compounds are developed. The electroluminescence characteristics of long-wavelength LEDs based on the proposed heterostructure, which emits in the spectral range of 4.6–5.3 μm, are studied. A linear decrease in the quantum efficiency of the electroluminescence with increasing InSb content in the active layer of the LEDs obtained is revealed. The advantage of using the asymmetric heterostructure for fabricating LEDs with a working wavelength of more than 4.5 μm is shown. [ABSTRACT FROM AUTHOR]

A hybrid double heterostructure with large asymmetric band offsets, combining AlAsSb/InAs (as a III-V part) and CdMgSe/CdSe (as a II-VI part), has been proposed as a basic element of a midinfrared laser structure design. The p-i-n diode structure has been successfully grown by molecular beam epitaxy and has exhibited an intense long-wavelength electroluminescence at 3.12 μm (300 K). A less than 10 times reduction of electroluminescence intensity from 77 to 300 K indicates an efficient carrier confinement in the InAs active layer due to high potential barriers in conduction and valence bands, estimated as ΔE[sub C]=1.28 eV and ΔE[sub V]∼1.6 eV. The type of band lineups at a coherent InAs/Cd[sub 1-x]Mg[sub x]Se interface is discussed for 0≤x≤0.15. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Ga0.84In0.16As0.22Sb0.78 quaternary solid solutions, lattice matched to InAs, were grown by liquid phase epitaxy on (100)-oriented p-InAs substrates from In-rich melt. The p-type Ga0.84In0.16As0.22Sb0.78 layers were intentionally undoped or slightly doped with Sn to the hole concentration about p∼5×1016 cm-3. This allowed us to obtain a high-mobility∼(3.5-5.0)×104 cm2 V-1 s-1 electron channel at the type II broken-gap p-Ga0.84In0.16As0.22Sb0.78/p-InAs heterointerface. Low-temperature (T=5 K) electroluminescence spectra exhibited two pronounced emission bands hν1=0.372 eV and hν2=0.400 eV under forward bias. The emission band hν2 was split into two lines and was attributed to interband transitions through acceptor and valence-band states in the bulk InAs, whereas emission band hν1 was ascribed to interface-related radiative transitions of electrons from the two-dimensional electron channel to the interface states at the p-Ga0.84In0.16As0.22Sb0.78/p-InAs heteroboundary. [ABSTRACT FROM AUTHOR]

The electroluminescence of the single unconfined type-II heterojunction p-GaInAsSb/p-InAs was investigated in the temperature range T = 4.2-77 K. As the temperature was reduced below T = 77 K, the luminescence bands with maxima at 311 meV (band A) and 384 meV (band B) were found to shift toward higher energies. At 4.2 K, the short-wave band split into two bands, B[sub 1] and B[sub 2]. These results are explained in terms of a model involving recombinations of electrons from the conduction band to an acceptor level of InAs, and also recombinations of electrons and holes localized in self-consistent quantum wells on either side of the heterojunction. [ABSTRACT FROM AUTHOR]

The electroluminescence appearing upon pulsed excitation in a solitary p-GaInAsSb/p-InAs typeII (broken-gap) heterostructure is investigated at T = 77 K. It is shown that just as in the case of excitation by a constant current, two emission bands with maxima corresponding to 384 and 311 meV, respectively, are observed in the spectra. The half-widths of the emission bands equal 18-19 meV. Time-resolved spectroscopy is used to evaluate the relaxation time of the nonequilibrium carriers, which amounts to 6-7 µs. The emission spectrum is calculated on the basis of the Kane model, and the radiative recombination time is estimated. The theoretical estimates are in reasonable agreement with experiment. [ABSTRACT FROM AUTHOR]