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

Using first‐principles band‐structure theory we have systematically calculated the (i) alloy bowing coefficients, (ii) alloy mixing enthalpies, and (iii) interfacial valence‐ and conduction‐band offsets for three mixed‐anion (CuInX2, X=S, Se, Te) and three mixed‐cation (CuMSe2, M=Al, Ga, In) chalcopyrite systems. The random chalcopyrite alloys are represented by special quasirandom structures (SQS). The calculated bowing coefficients are in good agreement with the most recent experimental data for stoichiometric alloys. Results for the mixing enthalpies and the band offsets are provided as predictions to be tested experimentally. Comparing our calculated bowing and band offsets for the mixed‐anion chalcopyrite alloys with those of the corresponding Zn chalcogenide alloys (ZnX, X=S, Se, Te), we find that the larger p−d coupling in chalcopyrite alloys reduces their band offsets and optical bowing. Bowing parameters for ordered, Zn‐based II‐VI alloys in the CuAu, CuPt, and chalcopyrite structures are present...

Band offsets and optical bowings of chalcopyrites and Zn‐based II‐VI alloys

Heterojunction band offset engineering

This paper is based on a comprehensive review of the literature and our own studies. We present a summary of the theoretical models and related empirical expressions to evaluate parameters related to the carrier transport within Si/SiGe heterostructures. The models and expressions include the effects of alloy composition and mechanical strain on the band structure of Si/SiGe alloys and the corresponding interfaces. They are presented in a form suitable for implementation in various types of device simulators. Important parameters, such as the band structure of strained or relaxed SiGe, the conduction and valence band offsets in the Si1−xGex/Si1−yGey heterostructures, the effective transport masses and the densities of states, have been calculated and shown to be in good agreement with existing experimental and theoretical results. Analytical expressions of those parameters as a function of Ge composition of the SiGe alloy have been given for strained Si on relaxed Si1−yGey substrate and strained Si1−xGex on Si substrate.

https://iopscience.iop.org/article/10.1088/0268-1242/19/10/002/pdf

Si/SiGe heterostructure parameters for device simulations

We review recent work in the application of Auger and X-ray photoelectron diffraction at high electron kinetic energies to the problem of structure determination in ultrathin epitaxial overlayers. These closely-related techniques are based on the fact that outgoing Auger and photoelectrons from single-crystal specimens undergo elastic scattering and interference from near-neighbour atoms in the vicinity of the emitter. Such coherent diffraction leads to large intensity modulations as the detected emission direction is varied with respect to the crystal axes of the specimen. The measured modulations are readily interpreted by means of model quantum mechanical scattering calculation in which atomic coordinates in the epitaxial film are systematically varied. Such analyses provide several kinds of useful information, including growth modes accompanying heteroepitaxy, structural details of alloy and compound formation, and quantitative determination of tetragonal distortion at lattice-mismatched hete...

Epitaxial film crystallography by high-energy Auger and X-ray photoelectron diffraction

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 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

We have used x-ray photoelectron spectroscopy to measure the valence band offset in situ for strained Si/Ge (100) heterojunctions and for AlSb/ZnTe (100) heterojunctions grown by molecular-beam epitaxy. For the Si/Ge system, Si 2p and Ge 3d core level to valence band edge binding energies and Si 2p to Ge 3d core level energy separations were measured as functions of strain, and strain configurations in all samples were determined using x-ray diffraction. Our measurements yield valence band offset values of 0.83±0.11 eV and 0.22±0.13 eV for Ge on Si (100) and Si on Ge (100), respectively. If we assume that the offset between the weighted averages of the light-hole, heavy-hole, and spin-orbit valence bands in Si and Ge is independent of strain, we obtain a discontinuity in the average valence band edge of 0.49±0.13 eV. For the AlSb/ZnTe (100) heterojunction system, we obtain a value of –0.42±0.07 eV for the valence band offset. Our data also suggest that an intermediate compound, containing Al and Te, is formed at the AlSb/ZnTe (100) interface.

/pdf/measurement-of-the-valence-band-offset-in-novel-ingkbmrn6g.pdf

Measurement of the valence band offset in novel heterojunction systems: Si/Ge (100) and AlSb/ZnTe (100)

We propose a new device structure for obtaining visible light emission from wide band gap semiconductors. This heterojunction structure avoids ohmic contacting problems by using only the doping types which tend to occur naturally in II-VI semiconductors, while using a novel injection scheme to obtain efficient minority carrier injection into the wider band gap semiconductor. To verify this proposal we have fabricated green light emitting structures using n-CdSe and p-ZnTe regions separated by a graded MgxCd1-xSe injection region. Room temperature electroluminescence spectra from these devices demonstrate the effectiveness of the injection scheme, while the current-voltage characteristics show the merits of avoiding difficult ohmic contacts. We further show how the structure can be extended to blue wavelengths and beyond by opening up the band gap of the ZnTe recombination region with a MgyZn1-yTe alloy.

/pdf/proposal-and-verification-of-a-new-visible-light-emitter-1otle9me9x.pdf

Proposal and verification of a new visible light emitter based on wide band gap II-VI semiconductors

We have used x-ray photoelectron spectroscopy (XPS) to measure the valence band offset in situ for CdSe/ZnTe (100) heterojunctions grown by molecular-beam epitaxy. XPS measurements were performed for films of CdSe (100) and ZnTe (100), and for heterojunctions consisting of either ~25 A of CdSe grown on ZnTe or ~25 A of ZnTe grown on CdSe. Observations of reflection high energy electron diffraction patterns indicated that CdSe films deposited on ZnTe were grown in cubic zinc blende form, rather than the natural wurtzite structure of CdSe. Our measurements yielded a CdSe/ZnTe valence band offset DeltaEv=0.64±0.07 eV. The corresponding conduction band offset for CdSe/ZnTe is DeltaEc=1.22±0.07 eV for room temperature band gaps for ZnTe and for cubic CdSe of 2.25 and 1.67 eV, respectively.

/pdf/measurement-of-the-cdse-znte-valence-band-offset-by-x-ray-59kiz2ln2y.pdf

M. C. Phillips

Papers

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

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

Measurement of the valence band offset in novel heterojunction systems: Si/Ge (100) and AlSb/ZnTe (100)

Proposal and verification of a new visible light emitter based on wide band gap II-VI semiconductors

Measurement of the CdSe/ZnTe valence band offset by x‐ray photoelectron spectroscopy