Ya. V. Terent’ev

Room-temperature 3.9–4.3 μm photoluminescence from InSb submonolayers grown by molecular beam epitaxy in an InAs matrix

We report on molecular beam epitaxial growth of InSb submonolayer insertions in an InAs matrix, exhibiting intense mid-IR photoluminescence (PL) up to room temperature (RT). The InSb insertions are fabricated by an exposure of InAs surface to an antimony Sb4 flux. The nominal thickness of insertions grown at different temperatures (TS=400–485°C) ranges from 0.6 to 1.4 monolayer, as estimated from x-ray diffraction measurements of InSb∕InAs multiple submonolayer structures. This gives rise to the variation of the emission wavelength within the 3.9–4.3 μm range at RT. An integral PL intensity drop from 77 K to RT does not exceed 20 times.

A 2.78-μm laser diode based on hybrid AlGaAsSb/InAs/CdMgSe double heterostructure grown by molecular-beam epitaxy

A mid-IR laser based on a hybrid pseudomorphic AlGaAsSb/InAs/CdMgSe heterostructure with a III–V/II–VI heterovalent interface at the 0.6-μm-InAs active region has been fabricated by molecular-beam epitaxy on p+-InAs substrate. It provides ∼1.5-eV asymmetric barriers for both electrons and holes in InAs, inhibiting carrier leakage from the active region. Despite a nonoptimal defect density at the CdMgSe/InAs interface (106–107 cm−2), the structure demonstrates lasing at ∼2.78 μm (up to 100 K) under pulse injection pumping with the threshold current density of 3–4 kA/cm2. The proposed design is promising for high-power mid-IR lasers operating at room temperature.

Room-temperature midinfrared electroluminescence from asymmetric AlSbAs/InAs/CdMgSe heterostructures grown by molecular beam epitaxy

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 ΔEC=1.28 eV and ΔEV∼1.6 eV. The type of band lineups at a coherent InAs/Cd1−xMgxSe interface is discussed for 0⩽x⩽0.15.

Temperature-dependent photoluminescence from type-II InSb∕InAs quantum dots

We report on the photoluminescence (PL) studies of InSb-enriched quantum dots (QDs) which are grown by molecular beam epitaxy in an InAs matrix. InSb∕InAs heterostructures have a nominal thickness of InSb insertions in the range of 0.6–2 monolayers and exhibit bright PL up to room temperature in the mid-infrared spectral range. The PL temperature dependence gives evidence that each InSb insertion can be regarded as an ensemble of QDs subject to carrier transfer even at low temperatures. Both QD PL energy and line-shape variations with temperature can be described employing Fermi-Dirac carrier statistics.

Midinfrared injection-pumped laser based on a III–V/II–VI hybrid heterostructure with submonolayer InSb insets

Lasing at 3.075 μm (T = 60 K) in a regime of pulsed injection pumping has been obtained in an AlGaAsSb/InAs/CdMgSe double hybrid heterostructure with the active region comprising an InAs layer with submonolayer InSb insets. The electroluminescence (EL) spectrum of the heterostructure has been studied for various values of the pumping current up to the stimulated emission threshold. An increase in the pumping current leads to a short-wavelength shift and a change in the EL band structure, which is explained by the occupation of higher states by the charge carriers in InSb quantum dots and/or in the adjacent InAsSb layer.

Spin polarized electric currents in semiconductor heterostructures induced by microwave radiation

We report on microwave (mw) radiation induced electric currents in semimagnetic CdMnTe and nonmagnetic InAs: Si quantum wells subjected to an external in-plane magnetic field. The current generation is attributed to the spin-dependent energy relaxation of electrons heated by mw radiation.

Metamorphic InAs/InGaAs/InAlAs quantum wells with submonolayer InSb insertions emitted in the mid-infrared spectral range

Metamorphic InAs/InGaAs/InAlAs quantum wells with submonolayer InSb insertions have been grown for the first time by molecular beam epitaxy on GaAs (001) substrates using a graded InAlAs buffer layer with increasing In composition. The given nanoheterostructures demonstrate an intense photoluminescence at a wavelength of over of over 3 μm (80 K), which is shifted toward longer wavelengths as compared with that of the structures without InSb insertions.

Exchange interaction of electrons with Mn in hybrid AlSb/InAs/ZnMnTe structures

Diluted magnetic semiconductor heterovalent AlSb/InAs/ZnMnTe quantum well (QW) structures with an electron channel have been designed and grown applying molecular-beam epitaxy. The enhanced magnetic properties of QWs as a result of the exchange interaction with Mn2+ ions, are proved by measuring the microwave radiation induced spin polarized electric currents.

Molecular beam epitaxy of thermodynamically metastable GaInAsSb alloys for medium IR-range photodetectors

The features of growth of GaInAsSb alloy with In content as high as 25 mol % lattice-matched to GaSb by molecular beam epitaxy are studied. These alloys are promising for use as the active region of photodetector structures of the mid-infrared range. The results of the study of these alloys by double-crystal X-ray diffractometry, scanning electron microscopy, and photoluminescence are presented. It is shown that the GaxIn1 − xAsySb1 − y alloys with x < 0.8 grown at 500°C show the degradation of structural and optical properties as the layer thickness is increased. In layers with thicknesses above the critical one, spinodal decomposition is observed in complete agreement with thermodynamic calculations of the location of the boundaries of immiscibility regions. The possibilities to optimize the molecular beam growth of the GaxIn1 − xAsySb1 − y alloys (x < 0.75) with high optical and structural quality, as well as the characteristics of photodetectors based on the GaInAsSb/AlGaAsSb heterostructures, are discussed.

MBE growth and photoluminescence properties of strained InAsSb/AlSbAs quantum wells

Summary form only given. The InAsSb/AlSbAs heterojunction system is promising for mid-infrared (2-5 /spl mu/m) lasers, since it combines the narrow band gap of an InAsSb alloy (< 0.4 eV at 77K) with a large conduction band offset at the hetero-boundary. The use of a strained quantum well (QW) active layer instead of thick InAsSb one is believed to increase the differential gain and reduce considerably the Auger recombination which limits the maximum operating temperature of such lasers. We report on MBE growth and photoluminescence (PL) properties of compressively strained InAsSb/AlSbAs single QW heterostructures. A set of norminally-undoped structures with well widths varying from 4 to 20 nm was grown pseudomorphically on GaSb [001] substrates using a two-stage growth regime. PL measurements of the structures were performed at 80K. Temperature and pump-power dependences of the PL intensities versus various structure parameters will be discussed.