The capabilities of metalorganic vapor-phase epitaxy (MOVPE) in fabrication of structures with thin (1–2 nm) alternating InAs/GaSb layers on a GaSb substrate are studied. The characteristics of these structures were examined using transmission electron microscopy and methods of photo- and electroluminescence. It was found that two GaInAsSb solid solutions of different compositions were formed in the active regions of structures in the given growth conditions. The fabricated system was characterized by an emission wavelength of 4.96 μm at a temperature of 77 K. The results reveal new opportunities for bandgap engineering of semiconductor structures based on InAs/GaSb, which are designed for optoelectronic devices operating in the infrared range, provided by MOVPE.

A system of Kane’s equations has been derived and solved with allowance for elastic stresses and nonsphericity of the kP Hamiltonian. On this basis, analytic expressions for the energy spectra of charge carriers have been obtained and calculations of the optical absorption coefficient for heavy holes with transition to a spin-orbit-split hole band in GaAs/InGaAs quantum wells (QWs) have been performed for various polarization directions of the incident radiation. It is established that the maximum absorption in GaAs/InGaAs heterostructure takes place at a QW width of 4–6 nm.

The system of Kane equations is derived and solved with taking into account the elastic stresses and the nonsphericity of the kP Hamiltonian. Analytical expressions for the energy spectra of charge carriers are obtained. The radiation absorption coefficient by heavy holes with transition to the spin-split zone in GaAs/InGaAs quantum wells was calculated for different directions of polarization of the incident radiation. It was shown that for the GaAs/InGaAs heterostructure, the maximum absorption will be observed when the QW width is 4–6 nm.

Capabilities of Metal Organic Chemical Vapor Deposition (MOCVD) method for fabrication of multi-layer InAs/GaSb structures with thin (1-2 nm) layers on GaSb substrates were studied. Properties of fabricated structures were studied by transmission electron microscopy and photo- and electro-luminescence. It was found that during growth, two solid solutions GaInAsSb of different compositions were formed in the active region of the structures. The system obtained is characterized by emission at the wavelength of 4.96 µm at the temperature 77 K. Our results demonstrate new capabilities of MOCVD method for bandgap engineering of semiconductor structures based on InAs/GaSb and designed for optoelectronic devices for infrared wavelength range.

A microscopic analysis of the mechanism of intraband radiation absorption by holes with their transition to a spin-split band for quantum wells based on stressed InGaAsP/InP quantum wells is performed within the framework of the four-band Kane model. The Kane’s equations are written and solved with taking into account nonsphericity of the kP Hamiltonian. It is shown that this process can be significant mechanism of internal radiation losses for quantum well lasers. It is shown that taking the nonsphericity and the elastic stresses into account leads to the absorption coefficient value decreasing. It is also shown that the maximum of the absorption coefficient is observed at values of the QW width from 40 to 60 A.

AbstractMicroscopic analysis of intraband radiation absorption by holes with their transition to the spin-split band for InAsSb/AlSb and InGaAsP/InP semiconductor quantum wells is performed in the context of the four-band Kane model. The calculation is performed for two incident-radiation polarizations: along the crystal-growth axis and in the quantum-well plane. It is demonstrated that absorption with transition to the discrete spectrum of spin-split holes has a higher intensity than absorption with transitions to the continuous spectrum. The dependences of the intraband absorption coefficient on temperature, hole density, and quantum- well width are thoroughly analyzed. It is shown that intraband radiation absorption can be the main mechanism of internal radiation losses in lasers based on quantum wells.

Microscopic analysis of intraband radiation absorption by holes with their transition to the spin-split band for InAsSb/AlSb and InGaAsP/InP semiconductor quantum wells is performed in the context of the four-band Kane model. The calculation is performed for two incident-radiation polarizations: along the crystal-growth axis and in the quantum-well plane. It is demonstrated that absorption with transition to the discrete spectrum of spin-split holes has a higher intensity than absorption with transitions to the continuous spectrum. The dependences of the intraband absorption coefficient on temperature, hole density, and quantum- well width are thoroughly analyzed. It is shown that intraband radiation absorption can be the main mechanism of internal radiation losses in lasers based on quantum wells.

The Kane's equations are written and solved with taking into account nonsphericity of the kp Hamiltonian. Charge carrier energy spectra and wave functions are obtained and analized. Subbands of dimensional quantization in the AlSb/InAs0.84Sb0.16/AlSb system are calculated with taking subband mixing into account. CHHS Auger process coefficient in the AlSb/InAs0.84Sb0.16/AlSb system is calculated with and without taking energy spectra nonsphericity and subband mixing into account. It is obtained that energy spectra nonsphericity and subband mixing lead to Auger matrix element and CHHS Auger process rate decrease.

The absorption coefficients of intersubband optical transitions in the valence band of the AlSb/InAs0.84Sb0.16/AlSb quantum wells in framework of the four-band Kane model. It is established that the light absorption by holes may lead to the laser generation breakdown. It is shown that we need to decrease the quantum well width to range a<6 nm to neutralize the negative influence of this effect.

The optical characteristics of heterostructures with deep quantum wells are studied using the AlSb/InAs 0.86 Sb 0.14 /AlSb structure within the framework of the four-band Kane model with regard to the nonparabolicity of the carrier energy spectrum. It is demonstrated that consideration of the nonparabolicity increases the number of size-quantization levels in the conduction band. At a quantum-well width of 100 Å, the investigated heterostructure contains three size-quantization levels within the parabolic model and six levels within the Kane model. This is due to the fact that the effective mass of high-energy electrons is found to be larger than the mass of electrons at the bottom of the conduction band by a factor of four. It is shown that account for the nonparabolicity only slightly affects the overlap integral for the s and p states, but significantly increases the density of states in the conduction band, which causes considerable growth in the radiation-absorption coefficient.

Optical properties of heterostructures with deep quantum wells have been studied in the framework of four-band Kane mode permitting a nonparabolic energy spectrum of charge carriers to be taken into account. The system AlSb/InAs0.84Sb0.16/AlSb was used as an example. It is established that the nonparabolicity weakly influences the overlap integral between s- and p-states, but notably increase the state density and optical absorption coefficient in the conduction band.

The optical characteristics of heterostructures with deep quantum wells have been studied by the example of the AlSb/InAs0.84Sb0.16/AlSb system with allowance for a non-parabolic energy spectrum of charge carriers in the framework of the four-band Kane model. It is established that the nonparabolicity weakly influences the overlap integral between s and p states, but leads to a significant increase in the density of states in the conduction band and, in turn, to a considerable growth in the optical absorption coefficient.

The current induced by the radiation from a 63Ni film of variable thickness is simulated taking into account the real spectrum of emitted electrons and their angular distribution for GaN. The efficiency of β-radiation detectors made from Si and SiC is estimated based on the results obtained in this paper and previously. Using a scanning electron microscope the efficiency of β-radiation detectors made from Si and SiC under conditions corresponding to β radiation from a Ni film with a thickness of 3 μm and activity of 10 mCi/cm2 is analyzed. It is shown that the efficiency of real Si-based structures is virtually as good as the efficiency of SiC-based structures.

Using the Kane model, the energy of the dimensional quantization levels, absorption coefficient, and radiative-recombination rate are calculated for interband optical transitions between different dimensional quantization subbands in a heterostructure with a deep AlSb/InAs0.86Sb0.14/AlSb quantum well with regard to and without regard for the spin-orbit interaction. It is shown that the corrections introduced by the spin-orbit interaction in calculating these quantities are no larger than a few tens of percent even at spin-orbit interaction constants exceeding the band gap and account for the nonparabolicity in the calculation of the energy of dimensional quantization levels and absorption coefficient is much more important than account for the spin-orbit interaction. In calculation of the radiative-recombination rate, both these effects should be taken into account.

Two-dimensional plasmon polaritons are analyzed for a typical experimental configuration in which a layer of two-dimensional electrons with a finite mobility lies on the top of a dielectric waveguide formed by the substrate (a wafer of finite thickness). Two-dimensional plasmons couple strongly to the radiative modes of this dielectric waveguide. It is shown that, as a result of the competition between collisional and radiative processes, a family of eight quasi-stationary normal modes arises. Six of them decay carrying energy to infinity. The two remaining plasmon-polariton modes are nonradiative. One of these modes, the TM-type plasmon polariton, in the limiting case where retardation is disregarded corresponds to the conventional longitudinal two-dimensional plasmon. The other mode, the TE-type plasmon polariton, exists only for a finite thickness of the substrate. All of them are characterized by different dispersion relations of the complex frequency ω(q) = Reω + iImω and differ in both polarization (longitudinal and transverse) and symmetry with respect to the direction of decay (symmetric and asymmetric). The latter modes decay slowly, propagating into free space to plus or minus infinity. The conditions under which the Q factors of certain modes are arbitrarily high are found. In this case, Imω(q 0) = 0, and dissipative losses in the two-dimensional electron gas are compensated by external sources. As a result, the reflection coefficient for a plane wave whose angle of incidence is determined by the vector q 0 vanishes.

Two line-by-line scanning modes of the X-ray-beam-induced current method—continuous and pointwise procedures—are compared. It is demonstrated that the continuous procedure makes it possible to achieve a severalfold decrease in the scanning duration without a significant influence on the resolution.

The current generated by radiation from a 63Ni layer of variable thickness is simulated with the actual spectrum of emitted electrons and with their distribution over the angles for Si and SiC taken into account. The dependences of the generation rate for nonequilibrium charge carriers on the depth are obtained for the cases of several Ni film thicknesses for both materials. The results are compared with the simulation results for a monoenergetic electron beam that is perpendicular to a semiconductor detector. It is shown that, for both Si and SiC, it is possible to choose an energy value of the electron beam in a SEM such that the ratio of the currents induced by the SEM beam and beta radiation from 63Ni is essentially independent of the diffusion length.

The mechanism of the radiative recombination of hot carriers in narrow-gap semiconductors is analyzed using the example of indium antimonide. It is shown that the CHCC Auger recombination process may lead to pronounced carrier heating at high excitation levels. The distribution functions and concentrations of hot carriers are determined. The radiative recombination rate of hot carriers and the radiation gain coefficient are calculated in terms of the Kane model. It is demonstrated that the radiative recombination of hot carriers will make a substantial contribution to the total radiative recombination rate at high carrier concentrations.