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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]

Abstract: Characteristic effects of magnetic ordering and conduction in semiconductor heterostructures with a GaAs : Be/Ga0.84In0.16As/GaAs quantum well and manganese δ-layers of different thickness (from 0.4 to 2 monolayers) were studied based on analysis of magnetic field and temperature dependences, galvanomagnetic effects, and magnetization. An anomalous dependence of the conductivity on the manganese atoms concentration in the δ-layer was observed, which was due to a strong scattering of charge carriers in the structures with the low content of magnetic impurities. Magnetic properties of the heterostructures clearly indicated the magnetic ordering of the impurity system (saturation and hysteresis of the magnetization and fulfillment of the Curie-Weiss law at increasing temperature). Parameters of the magnetic subsystem allowed revealing different types of ordering in the systems with different concentrations of the magnetic impurity. Changing the concentration of the Mn admixture in the δ-layer was shown to influence significantly the conductivity and magnetism in the studied structures. [ABSTRACT FROM AUTHOR]

Asymmetric n-InAs/InAs(1 –y)Sby/p-InAsSbP heterostructures with a narrow-gap active layer and a composition range y = 0.09–0.16 were grown by vapor phase epitaxy from metalorganic compounds. Room-temperature electroluminescence was observed at a wavelength of up to λ = 5.1 μm at a spectral maximum. The study of low-temperature electroluminescence spectra provided the possibility to establish the existence of two radiative recombination channels caused by the nature of the InAsSb/InAsSbP heterointerface. The effect produced by the chemistry of the active layer on the composition of the grown barrier layer and the formation of the InAsSb/InAsSbP heterojunction with an increase in the antimony content in the InAsSb solid solution was demonstrated. [ABSTRACT FROM AUTHOR]

Specific features of the energy spectrum of a separated type-II heterojunction in an external magnetic field are studied theoretically and experimentally. It is shown that, due to hybridization of the states of the valence band of one semiconductor and the conduction band of the other semiconductor at the heterointerface, there are level anticrossings, which produce quasigaps in the density of states in a nonzero magnetic field. The experimental results of magnetotransport studies for the GaInAsSb/p-InAs quaternary solid solutions with different doping levels are shown to agree well with the results of simulation, and specific features of the energy spectrum of separated type-II heterojunctions are established. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]