Surface doping of GaxIn1−xAs semiconductor crystals with magnesium

M. Yasir, J. Mäkelä, D. Koiva, M. Tuominen, J. Dahl, J.-P. Lehtiö, M. Kuzmin, Z. Jahanshah Rad, M. Punkkinen, P. Laukkanen, K. Kokko, V. Polojärvi, J. Lyytikäinen, A. Tukiainen, M. Guina

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    Effects of magnesium (Mg) alloying of GaxIn1−xAs(100) semiconductor surfaces have been investigated by low-energy electron diffraction, scanning tunneling microscopy/spectroscopy, and responsivity analysis of an infrared-detector component. In particular, the formation of an unusual Mg-induced (2 × 1) structure on GaAs(100) surfaces is found when depositing 1–3 monolayers of Mg on a cleaned GaAs(100) surface followed by annealing the sample in vacuum conditions at up to 500 °C. Concomitantly, the spectroscopy data show that the Fermi-level shifts toward valence band at the surface, indicating p-type doping of a surface part of GaAs due to Mg incorporation into the semiconductor. This surface-doping effect is also present in a test GaxIn1−xAs infrared detector, leading to increase in the detector responsivity. This beneficial effect of Mg-induced p-type doping is explained by a band-bending induced transfer of electrons away from a defect-rich top interface.
    Original languageEnglish
    Pages (from-to)33-36
    JournalMaterialia
    Volume2
    DOIs
    Publication statusPublished - Oct 2018
    Publication typeA1 Journal article-refereed

    Keywords

    • GaAs, Mg-induced reconstruction, Surface doping, STM, Infrared detector

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