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

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

Two dimensional electron gases in Al x Ga 12x N/GaN based heterostructures, suitable for high electron mobility transistors, are induced by strong polarization effects. The sheet carrier concentration and the confinement of the two dimensional electron gases located close to the AlGaN/GaN interface are sensitive to a large number of different physical properties such as polarity, alloy composition, strain, thickness, and doping of the AlGaN barrier. We have investigated these physical properties for undoped and silicon doped transistor structures by a combination of high resolution x-ray diffraction, atomic force microscopy, Hall effect, and capacitance‐voltage profiling measurements. The polarization induced sheet charge bound at the AlGaN/GaN interfaces was calculated from different sets of piezoelectric constants available in the literature. The sheet carrier concentration induced by polarization charges was determined

Two dimensional electron gases induced by spontaneous and piezoelectric polarization in undoped and doped AlGaN/GaN heterostructures

Recent research results pertaining to InN, GaN and AlN are reviewed, focusing on the different growth techniques of Group III-nitride crystals and epitaxial films, heterostructures and devices. The chemical and thermal stability of epitaxial nitride films is discussed in relation to the problems of deposition processes and the advantages for applications in high-power and high-temperature devices. The development of growth methods like metalorganic chemical vapour deposition and plasma-induced molecular beam epitaxy has resulted in remarkable improvements in the structural, optical and electrical properties. New developments in precursor chemistry, plasma-based nitrogen sources, substrates, the growth of nucleation layers and selective growth are covered. Deposition conditions and methods used to grow alloys for optical bandgap and lattice engineering are introduced. The review is concluded with a description of recent Group III-nitride semiconductor devices such as bright blue and white light-emitting diodes, the first blue-emitting laser, high-power transistors, and a discussion of further applications in surface acoustic wave devices and sensors.

https://iopscience.iop.org/article/10.1088/0022-3727/31/20/001/pdf

Growth and applications of Group III-nitrides

The valence‐band discontinuities at various wurtzite GaN, AlN, and InN heterojunctions were measured by means of x‐ray photoemission spectroscopy. A significant forward–backward asymmetry was observed in the InN/GaN–GaN/InN and InN/AlN–AlN/InN heterojunctions. The asymmetry was understood as a piezoelectric strain effect. We report the valence band discontinuities for InN/GaN=1.05±0.25 eV, GaN/AlN=0.70±0.24 eV, and InN/AlN=1.81±0.20 eV, all in the standard type I lineup. These values obey transitivity to within the experimental accuracy. Tables of photoemission core level binding energies are reported for wurtzite GaN, AlN, and InN.

Valence‐band discontinuities of wurtzite GaN, AlN, and InN heterojunctions measured by x‐ray photoemission spectroscopy

The valence‐band discontinuity at a wurtzite GaN/AlN(0001) heterojunction is measured by x‐ray photoemission spectroscopy. The method first measures the core level binding energies with respect to the valence‐band maximum in both GaN and AlN bulk films. The precise location of the valence‐band maximum is determined by aligning prominent features in the valence‐band spectrum with calculated densities of states. Tables of core level binding energies relative to the valence‐band maximum are reported for both GaN and AlN. Subsequent measurements of separations between Ga and Al core levels for thin overlayers of GaN film grown on AlN and vice versa yield a valence‐band discontinuity of ΔEV=0.8±0.3 eV in the standard type I heterojunction alignment.

Valence-band discontinuity between GaN and AlN measured by x-ray photoemission spectroscopy

Possible causes of a dense network of threading defects in epitaxial hexagonal GaN films grown on various substrates are discussed. We show that these defects originate at the substrate/film interface as the boundaries between differently stacked hexagonal domains, and are created by surface steps on substrates nonisomorphic with wurtzite GaN. We argue that these defects are inherent in the epitaxy of wurtzite films on nonisomorphic substrates. As a result, isomorphic substrates such as ZnO and GaN should be explored for wurtzite nitride growth. Possible effects of these defects on the properties of wurtzite nitrides are briefly discussed.

Formation of threading defects in GaN wurtzite films grown on nonisomorphic substrates

The effects of the Ga 3[ital d] semicore levels on the electronic structure of GaN are discussed. While band-structure theory using the local-density approximation predicts these states to overlap with the N 2[ital s] band and to have important effects on the total energy, x-ray photoelectron spectroscopy (XPS) shows that they occur [similar to]3 eV below the N 2[ital s] band. This apparent discrepancy is resolved by means of a so-called [Delta] SCF or difference of self-consistent-fields calculation, in which the binding energy is calculated as a total-energy difference including solid state screening effects by means of the excited-atom model. The calculated valence-band densities of states are found to be in good agreement with the XPS spectrum. The differences between zinc blende and wurtzite GaN are discussed.

X-ray photoelectron spectroscopy and theory of the valence band and semicore Ga 3d states in GaN.

We report on the current‐voltage (IV) characteristics of GaAs/GaN/GaAs semiconductor‐insulator‐semiconductor structures as a function of temperature. IV measurements show a strong temperature dependence indicating a thermal distribution of carriers flowing over a barrier. From these data we deduce an effective conduction band barrier of 0.9 eV between GaAs and GaN.

G. Martin

Papers

Valence‐band discontinuities of wurtzite GaN, AlN, and InN heterojunctions measured by x‐ray photoemission spectroscopy

Valence-band discontinuity between GaN and AlN measured by x-ray photoemission spectroscopy

Formation of threading defects in GaN wurtzite films grown on nonisomorphic substrates

X-ray photoelectron spectroscopy and theory of the valence band and semicore Ga 3d states in GaN.

Electrical properties of gaas/gan/gaas semiconductor-insulator-semiconductor structures