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

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.

Topics

• impedance spectroscopy
• surface
• electron diffraction
• Magnesium
• Magnesium
• semiconductor
• defect
• annealing
• x-ray absorption spectroscopy
• scanning tunneling microscopy