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

Various models for calculation of physical parameters in compound alloys are discussed and the results for In1−x Gax Asy P1−y quaternaries are presented. The model used is based on a linear interpolation scheme, and therefore necessitates known values of the parameters for the related binary and ternary alloys. The material parameters considered in the present study can be classified into the following eleven groups: (1) lattice constant and crystal density, (2) thermal expansion coefficient, (3) electronic‐band structure, (4) external perturbation effect on the lowest‐direct gap, (5) effective mass, (6) dielectric constant, (7) Frohlich coupling parameter, (8) elastic properties, (9) piezoelectric properties, (10) deformation potential, and (11) excitonic effect. Of particular interest is the deviation of material parameters from linearity with respect to the alloy composition. It is found that the present model provides generally acceptable parameters, in good agreement with the existing experimental da...

Material parameters of In1−xGaxAsyP1−y and related binaries

Solar-energy conversion usually takes one of two forms: the ‘quantum’ approach, which uses the large per-photon energy of solar radiation to excite electrons, as in photovoltaic cells, or the ‘thermal’ approach, which uses concentrated sunlight as a thermal-energy source to indirectly produce electricity using a heat engine. Here we present a new concept for solar electricity generation, photon-enhanced thermionic emission, which combines quantum and thermal mechanisms into a single physical process. The device is based on thermionic emission of photoexcited electrons from a semiconductor cathode at high temperature. Temperature-dependent photoemission-yield measurements from GaN show strong evidence for photon-enhanced thermionic emission, and calculated efficiencies for idealized devices can exceed the theoretical limits of single-junction photovoltaic cells. The proposed solar converter would operate at temperatures exceeding 200 °C, enabling its waste heat to be used to power a secondary thermal engine, boosting theoretical combined conversion efficiencies above 50%. The conversion of solar energy into electricity usually occurs either electrically or through thermal conversion. A new mechanism, photon-enhanced thermionic emission, which combines electric as well as thermal conversion mechanisms, is now shown to lead to enhanced conversion efficiencies that potentially could even exceed the theoretical limits of conventional photovoltaic cells.

Photon-enhanced thermionic emission for solar concentrator systems

Measurements of lattice parameters and compositions for In1−xGaxAsyP1−y lattice matched to InP demonstrate the validity of Vegard’s law for this quaternary. The measured compositional dependence of the band gap shows a bowing parameter smaller than predicted from the previously measured band gaps of the four constituent ternaries.

Band gap versus composition and demonstration of Vegard’s law for In1−xGaxAsyP1−y lattice matched to InP

The design, construction, operation, and performance of a spin polarized electron source utilizing photoemission from negative electron affinity (NEA) GaAs are presented in detail. A polarization of 43±2% is produced using NEA GaAs (100). The polarization can be easily modulated without affecting other characteristics of the electron beam. The electron beam intensity depends on the intensity of the exciting radiation at 1.6 eV; beam currents of 20 μA/mW are obtained. The source is electron optically bright; the emittance phase space (energy‐area‐solid angle product) is 0.043 eV mm2 sr. The light optics, electron optics, and cathode preparation including the GaAs cleaning and activation to NEA are discussed in depth. The origin of the spin polarization in the photoexcitation process is reviewed and new equations describing the depolarization of photoelectrons in the emission process are derived. Quantum yield and polarization measurements for both NEA and positive electron affinity surfaces are reported. T...

The GaAs spin polarized electron source

Published data for the composition dependence of the room-temperature bandgap (Eg) and lattice constant (ao) in the pseudobinary GayIn1-yAs, GayIn1-yP, GaAsxPl-x, and InAsxPl-x systems have been used to derive the following equations for the quaternary GayInl-yAsx Pl-x, alloys:

$$\begin{gathered} a_o ({\AA}) = 5.87 + 0.18x - 0.42y + 0.02xy \hfill \\ E_g (eV) = 1.35 - x + 1.4y - 0.33xy - (0.758 - 0.28x)y(1 - y) \hfill \\ - (0.101 + 0.109y) x(1 - x). \hfill \\ \end{gathered} $$

Bandgap and lattice constant of GaInAsP as a function of alloy composition

Electron energy loss in the band‐bending region of the p‐type III–V semiconductor in a III–V photocathode is an important factor in determining the escape probability and the optimum doping. From measurements of photoelectric yield near threshold from Cs2O‐activated n‐type GaAs, the position of the Fermi level at the GaAs–Cs2O interface was determined for {110}, {100}, {111A}, and {111B} surfaces. Assuming the Fermi‐level position at the GaAs surface to be independent of doping, the band bending for p‐type GaAs is greatest for the {111A} face and least for the {111B} face. The measured escape probabilities of photoexcited electrons from different crystalline faces of optimally activated 5 × 1018/cm3 Zn‐doped liquid epitaxial GaAs correlate well with the band‐bending measurements. The {111B} sample has an escape probability of 0.489 and a luminous sensitivity of 1837 μA/lm.

Dependence on Crystalline Face of the Band Bending in Cs2 O‐Activated GaAs

The conditions of growth of In1−xGaxAsyP1−y lattice‐matched to InP by the liquid‐phase epitaxy technique on (111) B‐oriented substrates have been analyzed in this paper. The epilayer composition has been varied from InP to In0.53Ga0.47As. The layer quality is more sensitive to experimental variables as the composition approaches the In0.53Ga0.47As side than when growing InP‐rich quaternaries. Hall measurements indicate the background doping to be in the low 1015/cm3 range if pure As and PH3 are used as the sources of the column‐V elements and the melt is baked at high temperature prior to growth.

Growth and characterization of InGaAsP–InP lattice‐matched heterojunctions

A method of obtaining efficient photoemission in the wavelength region from 1 to 2 μm, using the transferred‐electron effect in a p ‐type semiconductor, is proposed. Experimental demonstration of emission from InP in this mode is reported.

Transferred electron photoemission from InP

The organometallic vapor phase epitaxial growth of Ga1−xInxAs and GaAs1−ySby using trimethylarsenic and trimethylantimony as the Group V sources is reported and the relevant chemistry is discussed. Growth rate and composition variations as a function of temperature are given for GaAs1−ySby. A result of particular importance is that no detrimental room temperature gas phase reaction is observed between triethylindium and trimethylarsenic. Consequently, the growths are performed at one atmosphere pressure without the need for any complicated injection schemes in the reactor design.

R. L. Moon

Papers

Bandgap and lattice constant of GaInAsP as a function of alloy composition

Dependence on Crystalline Face of the Band Bending in Cs2 O‐Activated GaAs

Growth and characterization of InGaAsP–InP lattice‐matched heterojunctions

Transferred electron photoemission from InP

The organometallic VPE growth of GaAs1−ySby using trimethylantimony and Ga1−xInxAs using trimethylarsenic