Electronic band structure of highly mismatched GaN1−xSbx alloys in a broad composition range

Segercrantz, Natalie; Yu, K. M.; Min, Ting; Sarney, Wendy L.; Svensson, Stefan P.; Новиков, С. В.; Foxon, C. T.; Walukiewicz, W.

doi:10.1063/1.4932592

Cited by 26 publications

(21 citation statements)

References 33 publications

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Section: Optical Absorptionmentioning

confidence: 99%

Section: Electronic Band Structurementioning

confidence: 99%

“…The main deficiencies of the model were that it ignored the composition dependence of the coupling parameter and assumed that BAC interactions fully determine the shifts of the conduction and the valence band edges. To correct for the deficiencies we adopt here a hybrid model by using the VCA on the valence and conduction matrix band edges as well as on the potential of the anion lattice site [46]. Hence the coupling parameters for GaN1-xSbx are not constant but vary with composition.…”

Section: Electronic Band Structurementioning

confidence: 99%

“…The main deficiencies of the compositionally weighted BAC model are that it ignores direct dependence of the coupling parameter on composition and that it uses the endpoint CBE and VBE energies as the host matrix values. In order to address these deficiencies we have proposed a new hybrid BAC model [46] in which the composition dependence of CBE and VBE is separated into two contributions: the band edge shifts originating from a change of crystalline potential in the VCA and from a BAC interaction between localized states and the virtual crystal as a host matrix. This allows the BAC interactions to be treated as perturbations.…”

Section: The Modified Bac Modelmentioning

confidence: 99%

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Highly mismatched GaN_1−xSb_xalloys: synthesis, structure and electronic properties

Sarney

Новиков

et al. 2016

Semicond. Sci. Technol.

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Highly mismatched alloys (HMAs) is a class of semiconductor alloys whose constituents are distinctly different in terms of size, ionicity and/or electronegativity. Electronic properties of the alloys deviate significantly from an interpolation scheme based on small deviations from the virtual crystal approximation. Most of the HMAs were only studied in a dilute composition limit. Recent advances in understanding of the semiconductor synthesis processes allowed growth of thin films of HMAs under non-equilibrium conditions. Thus reducing the growth temperature allowed synthesis of group III-N-V HMAs over almost the entire composition range. This paper focuses on the GaNxSb1-x HMA which has been suggested as a potential material for solar water dissociation devices. Here we review our recent work on the synthesis, structural and optical characterization of GaN1-xSbx HMA. Theoretical modeling studies on its electronic structure based on the band anticrossing (BAC) model are also reviewed. In particular we discuss the effects of growth temperature, Ga flux and Sb flux on the incorporation of Sb, film microstructure and optical properties of the alloys. Results obtained from two separate MBE growths are directly compared. Our work demonstrates that a large range of direct bandgap energies from 3.4 eV to below 1.0 eV can be achieved for this alloy grown at low temperature. We show that the electronic band structure of GaN1-xSbx HMA over the entire composition range is well described by a modified the BAC model which includes the dependence of the host matrix band edges as well as the BAC model coupling parameters on composition. We emphasize that the modified BAC model of the electronic band structure developed for the full composition of GaNxSb1-x is general and is applicable to any HMA.

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Section: Optical Absorptionmentioning

confidence: 99%

Section: Electronic Band Structurementioning

confidence: 99%

Section: Electronic Band Structurementioning

confidence: 99%

Section: The Modified Bac Modelmentioning

confidence: 99%

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Highly mismatched GaN_1−xSb_xalloys: synthesis, structure and electronic properties

Sarney

Новиков

et al. 2016

Semicond. Sci. Technol.

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“…As shown in Figure 3 the bandgaps decrease with the Sb composition (measured by RBS) as predicted by a modified band anticrossing (BAC) model that is applicable to HMAs in the entire composition range [26]. The BAC model describes the perturbation of the GaN valence band by the localized Sb level.…”

Section: Fig 2 Measured and Intended Concentrations Of Sb In The Filmsmentioning

confidence: 99%

Intermixing studies in GaN_1−xSb_x highly mismatched alloys

et al. 2016

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GaN1−xSbx with x~ 5-7% is a highly mismatched alloy predicted to have favorable properties for application as an electrode in a photo-electrochemical cell for solar water splitting. In this study, we grew GaN1−xSbx under conditions intended to induce phase segregation. Prior experiments with the similar alloy GaN1−xAsx, the tendency of Sb to surfact, and the low growth temperatures needed to incorporate Sb, all suggested that GaN1−xSbx alloys would likely exhibit phase segregation. We found that, except for very high Sb compositions, this was not the case, and that instead interdiffusion dominated. Characteristics measured by optical absorption were similar to intentionally grown bulk alloys for the same composition. Furthermore, the alloys produced by this method maintained crystallinity for very high Sb compositions, and allowed higher overall Sb compositions. This method may allow higher temperature growth while still achieving needed Sb compositions for solar water splitting applications.

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Half‐Heusler compounds with a 1 eV (1.7 eV) direct band gap, lattice‐matched to GaAs (Si), for solar cell application: A first‐principles study

Belmiloud

Boutaiba

Belabbes

et al. 2016

Physica Status Solidi (b)

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A systematic theoretical study of the structural and electronic properties of new half‐Heusler compounds is performed to find the appropriate target key physical parameters for photovoltaic application. As a result, five ternary half‐Heusler compounds ScAgC, YCuC, CaZnC, NaAgO, and LiCuS are studied by density functional theory for potential applications in multi‐junction solar cells. The calculated formation enthalpies indicate that these materials are thermodynamically stable. Using state‐of‐the‐art modified Becke–Johnson exchange potential approximation, we find a direct band gap close to 1 eV (∼1.88 eV) for ScAgC, YCuC, CaZnC, NaAgO (LiCuS) being quasi‐lattice matched to GaAs (Si). In addition, the band offsets between half‐Heusler compounds and GaAs (Si) and their consequences for heterostructures are derived using the modified Tersoff method for the branch‐point energy. Furthermore, the elastic constants and phonon dispersion curves are calculated. They indicate the respective mechanical and dynamical stability of these half‐Heusler compounds.

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Electronic band structure of highly mismatched GaN1−xSbx alloys in a broad composition range

Cited by 26 publications

References 33 publications

Highly mismatched GaN_1−xSb_xalloys: synthesis, structure and electronic properties

Highly mismatched GaN_1−xSb_xalloys: synthesis, structure and electronic properties

Intermixing studies in GaN_1−xSb_x highly mismatched alloys

Half‐Heusler compounds with a 1 eV (1.7 eV) direct band gap, lattice‐matched to GaAs (Si), for solar cell application: A first‐principles study

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Electronic band structure of highly mismatched GaN1−xSbx alloys in a broad composition range

Cited by 26 publications

References 33 publications

Highly mismatched GaN1−xSbxalloys: synthesis, structure and electronic properties

Highly mismatched GaN1−xSbxalloys: synthesis, structure and electronic properties

Intermixing studies in GaN_1−xSb_x highly mismatched alloys

Half‐Heusler compounds with a 1 eV (1.7 eV) direct band gap, lattice‐matched to GaAs (Si), for solar cell application: A first‐principles study

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Product

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Highly mismatched GaN_1−xSb_xalloys: synthesis, structure and electronic properties

Highly mismatched GaN_1−xSb_xalloys: synthesis, structure and electronic properties