Donor levels and the microscopic structure of the DX center in n-type Si-doped AlxGa0.51-xIn0.49P grown by molecular-beam epitaxy

J. Mäkinen, T. Laine, Jatta Partanen, K. Saarinen, Pekka Hautojärvi, Kirsi Tappura, Timo Hakkarainen, Harri Asonen, Markus Pessa, J. Kauppinen, K. Vänttinen, M. Paalanen, Jari Likonen

    Research output: Contribution to journalArticleScientificpeer-review

    11 Citations (Scopus)


    We have investigated donor levels and the local structure of DX centers in Si-doped AlxGa0.51−xIn0.49P grown by gas-source molecular-beam epitaxy. In a ternary alloy Ga0.51In0.49P, Si donors form only shallow donor states. In contrast, in quaternary alloys with x≥0.25 a deep electron trapping center is observed. Hall measurements reveal an activated behavior of the mobile electron concentration, and the thermal binding energy of the dominant donor state is ∼0.1 eV when the Al fraction is x=0.25. Illumination with infrared or red light results in persistent photoconductivity at T≤120 K. The appearance of the DX level in the band gap around x≊0.1 gives a consistent picture of the experimental findings. Positron annihilation spectroscopy shows that the Si DX center is a vacancylike defect with a local structure equivalent to that found earlier in AlxGa1−xAs. The very different core shell structures of the group-III (Ga, In) and group-V (P) atoms give direct evidence that the vacancy has P atoms as its nearest neighbors and we identify it as a vacancy in the group-III sublattice. The structural data give support to the vacancy-interstitial model, which predicts that the donor impurities can take two different configurations in sp-bonded semiconductors.
    Original languageEnglish
    Pages (from-to)7851-7862
    Number of pages12
    JournalPhysical Review B: Condensed Matter
    Issue number12
    Publication statusPublished - 1996
    MoE publication typeA1 Journal article-refereed


    Dive into the research topics of 'Donor levels and the microscopic structure of the DX center in n-type Si-doped Al<sub>x</sub>Ga<sub>0.51-x</sub>In<sub>0.49</sub>P grown by molecular-beam epitaxy'. Together they form a unique fingerprint.

    Cite this