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

Yu, K.M.; Sarney, W.L.; Novikov, Sergei V.; Segercrantz, N.; Ting, M.; Shaw, M.; Svensson, S.P.; Martin, R.W.; Walukiewicz, W.; Foxon, C.T.

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


Authors

K.M. Yu

W.L. Sarney

Sergei V. Novikov

N. Segercrantz

M. Ting

M. Shaw

S.P. Svensson

R.W. Martin

W. Walukiewicz

C.T. Foxon



Abstract

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 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.

Citation

Yu, K., Sarney, W., Novikov, S. V., Segercrantz, N., Ting, M., Shaw, M., …Foxon, C. (2016). Highly mismatched GaN1−xSbxalloys: synthesis, structure and electronic properties. Semiconductor Science and Technology, 31(8), https://doi.org/10.1088/0268-1242/31/8/083001

Journal Article Type Article
Acceptance Date May 13, 2016
Publication Date Jun 28, 2016
Deposit Date Jul 18, 2016
Publicly Available Date Jul 18, 2016
Journal Semiconductor Science and Technology
Print ISSN 0268-1242
Electronic ISSN 1361-6641
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 31
Issue 8
DOI https://doi.org/10.1088/0268-1242/31/8/083001
Keywords Highly Mismatched Alloys, Nitride, Band Anticrossing, Electronic Band Structure, Photoelectrochemical Water Splitting
Public URL https://nottingham-repository.worktribe.com/output/793263
Publisher URL http://iopscience.iop.org/article/10.1088/0268-1242/31/8/083001/meta
Additional Information This is an author-created, un-copyedited version of an article accepted for publication in Semiconductor Science and Technology. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://iopscience.iop.org/article/10.1088/0268-1242/31/8/083001/meta

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