We present a comprehensive, up-to-date compilation of band parameters for the technologically important III–V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin-orbit, and crystal-field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split-off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy-composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.

Band parameters for III–V compound semiconductors and their alloys

A unipolar injection quantum cascade (QC) laser grown in an AlGaAs/GaAs material system by molecular beam epitaxy, is reported. The active material is a 30 period sequence of injectors/active regions made from Al0.33Ga0.67As/GaAs-coupled quantum wells. For this device a special waveguide design, which complies with a GaAs heavily doped substrate and very short Al0.90Ga0.10As cladding layers, has been optimized. At a heat-sink temperature of 77 K, the laser emission wavelength is 9.4 μm with peak optical power exceeding 70 mW and the threshold current density is 7.3 kA/cm2. The maximum operating temperature is 140 K. This work experimentally demonstrates the general validity of QC laser principles by showing laser action in a heterostructure material different from the one used until now.

GaAs/AlxGa1−xAs quantum cascade lasers

Time-resolved photoluminescence measurements reveal a minority carrier lifetime of >412 ns at 77 K under low excitation for a long-wavelength infrared InAs/InAs0.72Sb0.28 type-II superlattice (T2SL). This lifetime represents an order-of-magnitude increase in the minority carrier lifetime over previously reported lifetimes in long-wavelength infrared InAs/Ga1−xInxSb T2SLs. The considerably longer lifetime is attributed to a reduction of non-radiative recombination centers with the removal of Ga from the superlattice structure. This lifetime improvement may enable background limited T2SL long-wavelength infrared photodetectors at higher operating temperatures.

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Significantly improved minority carrier lifetime observed in a long-wavelength infrared III-V type-II superlattice comprised of InAs/InAsSb

Publisher Summary This chapter provides an overview of type-II superlattice infrared detectors. The type-II InAs/GaSb superlattices have several fundamental properties that make them suitable for infrared detection: (1) their band gaps can be made arbitrarily small by design, (2) they are more immune to band-to-band tunneling compared with bulk material, (3) the judicious use of strain in type-II InAs/GaInSb strained layer superlattice (SLS) can enhance its absorption strength over that of the type-II InAs/GaSb superlattice to a level comparable with HgVdTe (MCT), and (4) type-II InAs/Ga(In)Sb superlattices also reduce Auger recombination. In addition, the dark current characteristics of type-II superlattice-based single element long-wavelength infrared (LWIR) detectors are currently approaching state-of-the-art MCT detector. Noise measurements highlight the need for surface leakage suppression, which can be tackled by improved etching, passivation, and device design. The chapter also describes the principles behind advanced superlattice infrared detectors based on heterostructure designs. It also explores some aspects of device fabrication and characterization.

Type-II Superlattice Infrared Detectors

We analyze and compare different aspects of InAs/InAsSb and InAs/GaSb type-II superlattices for infrared detector applications and argue that the former is the most effective when implemented for mid-wavelength infrared detectors. We then report results on an InAs/InAsSb superlattice based mid-wavelength high operating temperature barrier infrared detector. At 150 K, the 50% cutoff wavelength is 5.37 μm, the quantum efficiency at 4.5 μm is ∼52% without anti-reflection coating, the dark current density under −0.2 V bias is 4.5 × 10−5 A/cm2, and the dark-current-limited and the f/2 black-body (300 K background in 3–5 μm band) specific detectivities are 4.6 × 1011 and 3.0 × 1011 cm-Hz1/2/W, respectively. A focal plane array made from the same material exhibits a mean noise equivalent differential temperature of 18.7 mK at 160 K operating temperature with an f/2 optics and a 300 K background, demonstrating significantly higher operating temperature than InSb.

Mid-wavelength high operating temperature barrier infrared detector and focal plane array

Room-temperature pump-probe transmission experiments have been performed on an arsenic-rich InAs/InAs1-xSbx strained layer superlattice (SLS) above the fundamental absorption edge near 10 mu m, using a ps far-infrared free-electron laser. Measurements show complete bleaching at the excitation frequency, with recovery times which are found to be strongly dependent on the pump photon energy. At high excited carrier densities, corresponding to high photon energy and interband absorption coefficient, the recombination is dominated by Auger processes, A direct comparison with identical measurements on epilayers of InSb, of comparable room-temperature band gap, shows that the Auger processes have been substantially suppressed in the superlattice case as a result of both the quantum confinement and strain splittings in the SLS structure, In the nondegenerate regime, where the Auger lifetime scales as tau(aug)(-1)=C1Ne2, a value of C-1 some 100 times smaller is obtained for the SLS structure. The results have been interpreted in terms of an 8x8 k . p SLS energy band calculation, including the full dispersion for both k in plane and k parallel to the growth direction. This is the strongest example of room-temperature Auger suppression observed to date for these long-wavelength SLS alloy compositions and implies that these SLS materials may be attractive for applications as room-temperature mid-IR diode lasers. (C) 1996 American institute of Physics.

Suppression of Auger recombination in arsenic‐rich InAs1−xSbx strained layer superlattices

Arsenic-rich InAs/lnAs1-xSbx strained layer superlattices (SLSs) grown on GaAs substrates by molecular beam epitaxy (MBE) are studied for their potential application as infrared emitters. The long-wavelength emission (4-11 mu m) is highly sensitive to superlattice design parameters and is accounted for by a large type-II band offset, greater than in previously studied antimony-rich InSb/lnAs1-xSbx SLSs. High internal PL efficiencies (>10%) and intense luminescence emission were observed at these long wavelengths despite large dislocation densities. Initial unoptimized InAs/lnAs1-xSbx SLS light emitting diodes gave approximately=200 nW of lambda =5 mu m emission at 300 K.

https://iopscience.iop.org/article/10.1088/0268-1242/10/8/023/pdf

4-11 mu m infrared emission and 300 K light emitting diodes from arsenic-rich InAs1-xSbx strained layer superlattices

A midinfrared picosecond spectrometer based on an ${\mathrm{Er}}^{3+}$ laser-pumped optical parametric generator has been used to study Auger recombination processes in intrinsic InSb at room temperature. After carrier excitation by a 100-psec \ensuremath{\lambda}=2.8 \ensuremath{\mu}m ${\mathrm{Er}}^{3+}$ laser pulse the sample transmission change due to excess carriers was probed, using short pulses of wavelengths varying in the range 4--6 \ensuremath{\mu}m, as a function of time delay. It was shown that over the measured range of carrier densities (n=${10}^{16}$--${10}^{18}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$) the momentum-conserving conduction--heavy-hole--heavy-hole--light-hole Auger process was the predominant channel for electron-hole recombination with a quadratic rather than a cubic dependence of recombination rate on carrier density. The effective Auger lifetime scales as ${\mathrm{\ensuremath{\tau}}}_{\mathrm{Aug}}^{1\mathrm{\ensuremath{-}}}$=${\mathit{C}}_{2}$n with ${\mathit{C}}_{2}$=7.4(\ifmmode\pm\else\textpm\fi{}1.5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}9}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. This type of carrier concentration dependence is in accordance with theoretical predictions for semiconductors in which the electron component of the carrier population is degenerate.

Midinfrared picosecond spectroscopy studies of Auger recombination in InSb.

The band alignments and band offsets were investigated for In(As,Sb)/InAs superlattices of various periods and compositions. Magnetoabsorption experiments allowed identification of subband energies and in-plane reduced masses. Using an 8\ifmmode\times\else\texttimes\fi{}8 k\ensuremath{\cdot}p band-structure calculation which takes account of nonparabolicity, valence subband mixing, and strain effects, we are able to fit calculated absorption curves to transition energies and reduced masses. Comparison of fits on several samples confirm that the electrons lie in the In(As,Sb) layer and the holes in the InAs layer. By using the fitted curve offsets, we are able to calculate the fractional conduction-band-offset parameter, ${\mathrm{Q}}_{\mathrm{c}}$, which for a type-II heterostructure can be greater than 1 and which we found to be 2.06\ifmmode\pm\else\textpm\fi{}0.11.

Band alignments and offsets in in(as,sb)inas superlattices

InAs/InAs0.865Sb0.135 quantum wells are characterized using magneto‐photoluminescence. Band‐ to‐band transitions are found at energies lower than the band gaps of either the InAs or the InAs0.865Sb0.135 with photoluminescence emission at wavelengths up to 4.8 μm. By modeling the quantum size shifts of the photoluminescence transitions and their energy shift in a magnetic field, the valence band offset between InAs and In(As,Sb) is deduced to be type II with electron confinement in the In(As,Sb) alloy and hole confinement in InAs.

C. C. Phillips

Papers

Suppression of Auger recombination in arsenic‐rich InAs1−xSbx strained layer superlattices

4-11 mu m infrared emission and 300 K light emitting diodes from arsenic-rich InAs1-xSbx strained layer superlattices

Midinfrared picosecond spectroscopy studies of Auger recombination in InSb.

Band alignments and offsets in in(as,sb)inas superlattices

A magneto-photoluminescence investigation of the band offset between inas and arsenic-rich inas1-xsbx alloys