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

Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure (DH) blue‐light‐emitting diodes(LEDs) with the luminous intensity over 1 cd were fabricated As an active layer, a Zn‐doped InGaN layer was used for the DH LEDs The typical output power was 1500 μW and the external quantum efficiency was as high as 27% at a forward current of 20 mA at room temperature The peak wavelength and the full width at half‐maximum of the electroluminescence were 450 and 70 nm, respectively This value of luminous intensity was the highest ever reported for blue LEDs

Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure blue‐light‐emitting diodes

Carrier concentration profiles of two-dimensional electron gases are investigated in wurtzite, Ga-face AlxGa1−xN/GaN/AlxGa1−xN and N-face GaN/AlxGa1−xN/GaN heterostructures used for the fabrication of field effect transistors. Analysis of the measured electron distributions in heterostructures with AlGaN barrier layers of different Al concentrations (0.15<x<0.5) and thickness between 20 and 65 nm demonstrate the important role of spontaneous and piezoelectric polarization on the carrier confinement at GaN/AlGaN and AlGaN/GaN interfaces. Characterization of the electrical properties of nominally undoped transistor structures reveals the presence of high sheet carrier concentrations, increasing from 6×1012 to 2×1013 cm−2 in the GaN channel with increasing Al-concentration from x=0.15 to 0.31. The observed high sheet carrier concentrations and strong confinement at specific interfaces of the N- and Ga-face pseudomorphic grown heterostructures can be explained as a consequence of interface charges induced by ...

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Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures

We present a comprehensive and up-to-date compilation of band parameters for all of the nitrogen-containing III–V semiconductors that have been investigated to date. The two main classes are: (1) “conventional” nitrides (wurtzite and zinc-blende GaN, InN, and AlN, along with their alloys) and (2) “dilute” nitrides (zinc-blende ternaries and quaternaries in which a relatively small fraction of N is added to a host III–V material, e.g., GaAsN and GaInAsN). As in our more general review of III–V semiconductor band parameters [I. Vurgaftman et al., J. Appl. Phys. 89, 5815 (2001)], complete and consistent parameter sets are recommended on the basis of a thorough and critical review of the existing literature. We tabulate the direct and indirect energy gaps, spin-orbit and crystal-field splittings, alloy bowing parameters, electron and hole effective masses, deformation potentials, elastic constants, piezoelectric and spontaneous polarization coefficients, as well as heterostructure band offsets. Temperature an...

Band parameters for nitrogen-containing semiconductors

In the past several years, research in each of the wide‐band‐gap semiconductors, SiC, GaN, and ZnSe, has led to major advances which now make them viable for device applications. The merits of each contender for high‐temperature electronics and short‐wavelength optical applications are compared. The outstanding thermal and chemical stability of SiC and GaN should enable them to operate at high temperatures and in hostile environments, and also make them attractive for high‐power operation. The present advanced stage of development of SiC substrates and metal‐oxide‐semiconductor technology makes SiC the leading contender for high‐temperature and high‐power applications if ohmic contacts and interface‐state densities can be further improved. GaN, despite fundamentally superior electronic properties and better ohmic contact resistances, must overcome the lack of an ideal substrate material and a relatively advanced SiC infrastructure in order to compete in electronics applications. Prototype transistors have been fabricated from both SiC and GaN, and the microwave characteristics and high‐temperature performance of SiC transistors have been studied. For optical emitters and detectors, ZnSe, SiC, and GaN all have demonstrated operation in the green, blue, or ultraviolet (UV) spectra. Blue SiC light‐emitting diodes (LEDs) have been on the market for several years, joined recently by UV and blue GaN‐based LEDs. These products should find wide use in full color display and other technologies. Promising prototype UV photodetectors have been fabricated from both SiC and GaN. In laser development, ZnSe leads the way with more sophisticated designs having further improved performance being rapidly demonstrated. If the low damage threshold of ZnSe continues to limit practical laser applications, GaN appears poised to become the semiconductor of choice for short‐wavelength lasers in optical memory and other applications. For further development of these materials to be realized, doping densities (especially p type) and ohmic contact technologies have to be improved. Economies of scale need to be realized through the development of larger SiC substrates. Improved substrate materials, ideally GaN itself, need to be aggressively pursued to further develop the GaN‐based material system and enable the fabrication of lasers. ZnSe material quality is already outstanding and now researchers must focus their attention on addressing the short lifetimes of ZnSe‐based lasers to determine whether the material is sufficiently durable for practical laser applications. The problems related to these three wide‐band‐gap semiconductor systems have moved away from materials science toward the device arena, where their technological development can rapidly be brought to maturity.

Large‐band‐gap SiC, III‐V nitride, and II‐VI ZnSe‐based semiconductor device technologies

Wurtzite InN films were grown on a thick GaN layer by metalorganic vapor phase epitaxy. Growth of a (0001)-oriented single crystalline layer was confirmed by Raman scattering, x-ray diffraction, and reflection high energy electron diffraction. We observed at room temperature strong photoluminescence (PL) at 0.76 eV as well as a clear absorption edge at 0.7–1.0 eV. In contrast, no PL was observed, even by high power excitation, at ∼1.9 eV, which had been reported as the band gap in absorption experiments on polycrystalline films. Careful inspection strongly suggests that a wurtzite InN single crystal has a true bandgap of 0.7–1.0 eV, and the discrepancy could be attributed to the difference in crystallinity.

Optical bandgap energy of wurtzite InN

InGaN single‐crystal films were grown on (0001) plane sapphire substrates at 800 °C by metalorganic vapor phase epitaxy. By using such a high temperature for growth, the crystalline quality has been greatly improved. But a high nitrogen over pressure and high indium source flow rate were necessary to achieve significant indium incorporation during growth. For the first time, photoluminescence has been observed in InGaN, and near‐band edge emission is seen in the photoluminescence at 77 K. From this photoluminescence, the dependence of a near‐band edge emission on the indium mole fraction of InGaN has been investigated.

Photoluminescence of InGaN films grown at high temperature by metalorganic vapor phase epitaxy

We have achieved InGaN growth on sapphire substrates at temperatures substantially higher than conventional growth temperatures for InGaN. When the growth temperature was changed from 500 (conventional) to 800° C (this work) in InGaN, the x-ray diffraction line width (full width at half maximum) decreased from 100 to 30 min. At 77 K, edge emission was observed in PL. In order to further improve crystalline quality, we have investigated ZnO as a lattice-matching substrate. First, the surface treatment and the resistance to the reducing atmosphere at high temperatures was briefly investigated. We report the first successful lattice-matched growth of InGaN. The x-ray diffraction line width of InGaN grown on ZnO was about 20% smaller than that of films grown on sapphire substrates, thus using lattice-matched substrates was shown to have an effect on improving the crystalline quality of InGaN. Single crystal InGaAlN has been also realized on sapphire substrates. The indium, gallium and aluminum contents were 2.2, 22.5 and 74.3%, respectively. The optical transmission characteristic of this InGaAlN was measured.

Wide-gap semiconductor InGaN and InGaALN grown by MOVPE

Single‐crystal gallium nitride was grown on each of the two polar {0001} planes of 6H‐silicon carbide substrates utilizing metal‐organic vapor‐phase epitaxy. The substrate polarity is clearly shown to strongly influence the surface morphology and the photoluminescence property of the layer. The examination of the layer surfaces using x‐ray photoelectron spectroscopy revealed that {0001} GaN grown on the basal planes of SiC changes its polarity in accordance with the substrate polarity.

Substrate-polarity dependence of metal-organic vapor-phase epitaxy-grown GaN on SiC

The wurtzite structure In1−x−yGaxAlyN quaternary system with a wide band gap, which is useful for light emitters in the wavelength region shorter than green, is studied with respect to the unstable region in mixing. This unstable region in mixing is calculated from the free energy of mixing using the strictly regular solution model. The interaction parameter used in this calculation is obtained using the delta-lattice-parameter method. From this calculation, the ternary alloys of InAlN, InGaN, and GaAlN are, respectively, predicted to always, sometimes, and hardly ever have a unstable mixing region at the temperature lower than 3000 °C.

Takashi Matsuoka

Papers

Optical bandgap energy of wurtzite InN

Photoluminescence of InGaN films grown at high temperature by metalorganic vapor phase epitaxy

Wide-gap semiconductor InGaN and InGaALN grown by MOVPE

Substrate-polarity dependence of metal-organic vapor-phase epitaxy-grown GaN on SiC

Calculation of unstable mixing region in wurtzite In1-x-yGaxAlyN