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

We compare basic physical parameters of Al/sub 0.2/Ga/sub 0.8/N-GaN quantum well with In/sub 0.17/Al/sub 0.83/N/GaN and In/sub 0.17/Al/sub 0.83/N/In/sub 0.10/Ga/sub 0.90/N quantum well parameters, respectively. It is shown that in comparison to conventional AlGaN/GaN approach, structures based on InAlN/(In)GaN should exhibit two to three times higher quantum well polarization-induced charge. We use high electron mobility transistors (HEMT) analytical model to calculate InAlN(In)GaN HEMTs drain currents and transconductances. A 3.3 A/mm and 2.2 A/mm drain current was calculated for In/sub 0.17/Al/sub 0.83/N/In/sub 0.10/Ga/sub 0.90/N and In/sub 0.17/Al/sub 0.83/N/GaN HEMTs, respectively. This represents up to 205% current increase if compared with AlGaN/GaN HEMT and a record power performance can be expected for new structures.

Power electronics on InAlN/(In)GaN: Prospect for a record performance

Heterojunction band offset engineering

High-conductivity two-dimensional electron gases at AlN∕GaN heterojunctions are reported. The sheet densities can be tuned from ∼5×1012∕cm2to∼5×1013∕cm2 by varying the AlN thickness from 2to7nm. A critical thickness is observed beyond which biaxial strain relaxation and cracking of AlN occur, and a degradation of carrier mobility is seen to occur at extremely high sheet densities. A high-mobility window is identified, within which room-temperature mobility exceeding 1000cm2∕Vs. and sheet densities in the (1–3)×1013∕cm2 are obtained, yielding record low sheet resistances in the range of ∼170Ω∕◻. Interface roughness scattering and strain relaxation are identified as the factors preventing lower sheet resistances at present.

High-mobility window for two-dimensional electron gases at ultrathin AlN∕GaN heterojunctions

Znx Cd1-x S single-crystal nanoribbons of controlled composition (where 0 ≤ x ≤ 1) can be synthesized by combining laser ablation with thermal evaporation. The nanoribbons exhibit lasing emission that can be continuously tuned within the ranges of 340-390 nm and 485-515 nm. These results suggest that Znx Cd1-x S nanoribbon lasers of pre-selected "tunable" wavelengths between 340 and 515 nm may be achievable by tailoring the value of x.

Wavelength-Controlled Lasing in ZnxCd1–xS Single-Crystal Nanoribbons†

An overview is presented of band alignments for small-lattice parameter, refractory semiconductors. The band alignments are estimated empirically through the use of available Schottky barrier height data, and are compared to theoretically predicted values. Results for tetrahedrally bonded semiconductors with lattice constant values in the range from C through ZnSe are presented. Based on the estimated band alignments and the recently demonstrated p-type dopability of GaN, we propose three novel heterojunction schemes which seek to address inherent difficulties in doping or electrical contact to wide-gap semiconductors such as ZnO, ZnSe, and ZnS.

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Schottky-based band lineups for refractory semiconductors

The only II‐VI/II‐VI wide band‐gap heterojunction to provide both good lattice match and p‐ and n‐type dopability is CdSe/ZnTe. We have carried out numerical simulations of several light emitter designs incorporating CdSe, ZnTe, and Mg alloys. In the simulations, Poisson’s equation is solved in conjunction with the hole and electron current and continuity equations. Radiative and nonradiative recombination in bulk material and at interfaces are included in the model. Simulation results show that an n‐CdSe/p‐ZnTe heterostructure is unfavorable for efficient wide band‐gap light emission due to recombination in the CdSe and at the CdSe/ZnTe interface. An n‐CdSe/Mg_(x)Cd_(1−x)Se/p‐ZnTe heterostructure significantly reduces interfacial recombination and facilitates electron injection into the p‐ZnTe layer. The addition of a Mg_(y)Zn_(1−y)Te electron confining layer further improves the efficiency of light emission. Finally, an n‐CdSe/Mg_(x)Cd_(1−x)Se/Mg_(y)Zn_(1−y)Te/p‐ZnTe design allows tunability of the wavelength of light emission from green into the blue wavelength regime.

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n‐CdSe/p‐ZnTe based wide band‐gap light emitters: Numerical simulation and design

We present reflection high energy electron diffraction, secondary ion mass spectroscopy, scanning tunneling microscopy and x‐ray photoelectron spectroscopy studies of the abruptness of InAs–GaSb interfaces. We find that the interface abruptness depends on growth order: InAs grown on GaSb is extended, while GaSb grown on InAs is more abrupt. We first present observations of the interfacial asymmetry, including measurements of band alignments as a function of growth order. We then examine more detailed studies of the InAs–GaSb interface to determine the mechanisms causing the extended interface. Our results show that Sb incorporation into the InAs overlayer and As exchange for Sb in the GaSb underlayer are the most likely causes of the interfacial asymmetry.

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Study of interface asymmetry in InAs–GaSb heterojunctions

We have used x-ray photoelectron spectroscopy to measure the valence-band offsets for the lattice matched MgSe/Cd0.54Zn0.46Se and MgTe/Cd0.88Zn0.12Te heterojunctions grown by molecular beam epitaxy. By measuring core level to valence-band maxima and core level to core level binding energy separations, we obtain values of 0.56+/-0.07 eV and 0.43+/-0.11 eV for the valence-band offsets of MgSe/Cd0.54Zn0.46Se and MgTe/Cd0.88Zn0.12Te, respectively. Both of these values deviate from the common anion rule, as may be expected given the unoccupied cation d orbitals in Mg. Application of our results to the design of current II-VI wide band-gap light emitters is discussed.

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X‐ray photoelectron spectroscopy measurement of valence‐band offsets for Mg‐based semiconductor compounds

Scanning tunneling microscopy and spectroscopy is used to characterize InAs/GaSb superlattices, grown by molecular‐beam epitaxy. Roughness at the interfaces between InAs and GaSb layers is directly observed in the images, and a quantitative spectrum of this roughness is obtained. Electron subbands in the InAs layers are resolved in spectroscopy. Asymmetry between the interfaces of InAs grown on GaSb compared with GaSb grown on InAs is seen in voltage‐dependent imaging. Detailed spectroscopic study of the interfaces reveals some subtle differences between the two in terms of their valence‐band onsets and conduction‐band state density. These differences are interpreted in a model in which the GaSb on InAs interface has an abrupt InSb‐like structure, but at the InAs on GaSb interface some Sb grading occurs into the InAs overlayer.

M. W. Wang

Papers

Schottky-based band lineups for refractory semiconductors

n‐CdSe/p‐ZnTe based wide band‐gap light emitters: Numerical simulation and design

Study of interface asymmetry in InAs–GaSb heterojunctions

X‐ray photoelectron spectroscopy measurement of valence‐band offsets for Mg‐based semiconductor compounds

Scanning tunneling microscopy of InAs/GaSb superlattices: Subbands, interface roughness, and interface asymmetry