Formation of Minibands on Superlattice Structure with Periodically Arranged $\delta$-Doped Nitrogen into GaAs

Using molecular beam epitaxy, we fabricate a superlattice structure having periodically arranged $\delta$-doped nitrogen within GaAs. X-ray diffraction indicates the formation of regularly arranged 0.1 ML $\delta$-doped nitrogen having a certain dispersion every 3.7 nm, multilayered up to 10 periods...

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Bibliographic Details
Published inApplied physics express Vol. 6; no. 4; pp. 041002 - 041002-4
Main Authors Sumiya, Kengo, Morifuji, Masato, Oshima, Yoshifumi, Ishikawa, Fumitaro
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.04.2013
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Summary:Using molecular beam epitaxy, we fabricate a superlattice structure having periodically arranged $\delta$-doped nitrogen within GaAs. X-ray diffraction indicates the formation of regularly arranged 0.1 ML $\delta$-doped nitrogen having a certain dispersion every 3.7 nm, multilayered up to 10 periods. Optical transition energies obtained from photoreflectance reflect the number of superlattice periods. That suggests the formation of minibands in the short-period GaAsN/GaAs quantum wells, as well as the dispersed distribution of the nitrogen about ${\sim}7$ ML as also predicted from transmission electron microscopy.
Bibliography:Sample structure. Cross-sectional BF-STEM image of the sample with 2-period $\delta$-doped layers. Experimental and simulated $\omega$--$2\theta$ XRD scans across GaAs(004) reflection, for samples containing single $\delta$-doped layers and superlattices with 3-period and 10-period. The dot-dashed lines are an extrapolation of the experimental signal close to the main peak of the 3-period sample. The line is multiplied and superimposed on the curve of the single-period sample, suggesting the enhancement of the right shoulder for the 3-period sample. XRD reciprocal space mapping around GaAs($\bar{2}\bar{2}4$) reflection for 10-period $\delta$-doped sample. PR spectra for the superlattice samples. Experimental data are plotted with filled circles. Theoretical fits using Aspnes' function are shown by red-colored solid lines. The inset displays overall spectra, and the enlarged regions are indicated by the dashed box. Considered band structure and calculated energy levels for sample having 1, 3, and 10 superlattice periods, assuming each $\delta$-doped nitrogen has its nitrogen dispersion over 7 ML. Comparison between the experimentally obtained PR transition and PL peak energies, and theoretically obtained transition energies for the superlattice structure. The calculations were carried out for each assumed nitrogen distribution adjusting $C_{\text{NM}}$ to fit the energy of a single-period sample. Then, by increasing the number of superlattice periods, we obtained the trend of the transition energies.
ISSN:1882-0778
1882-0786
DOI:10.7567/APEX.6.041002