A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Local variation in Bi crystal sites of epitaxial GaAsBi studied by photoelectron spectroscopy and first-principles calculations

Julkaisun tekijät: P. Laukkanen, M.P.J. Punkkinen, A. Lahti, J. Puustinen, M. Tuominen, J. Hilska, J. Mäkelä, J. Dahl, M. Yasir, M. Kuzmin, J.R. Osiecki, K. Schulte, M. Guina, K. Kokko
Julkaisuvuosi: 2017
Journal: Applied Surface Science
Volyymi: 396
Sivujen määrä: 7
eISSN: 1873-5584


Epitaxial Bi-containing III–V crystals (III-V1-xBix) have attracted increasing interest due to their potential in infrared applications. Atomic-scale characterization and engineering of bulk-like III-V1-xBix properties (e.g., Bi incorporation and defect formation) are challenging but relevant to develop applications. Toward that target, we report here that the traditional surface-science measurement of photoelectron spectroscopy (PES) is a potential, non-destructive method to be combined in the studies of bulk-like properties, when surface effects are properly removed. We have investigated epitaxial GaAs1-xBix films, capped by epitaxial AlAs layers, with high-resolution photoelectron spectroscopy. The Bi5d core-level spectra of GaAs1-xBixtogether with ab-initio calculations give direct evidence of variation of Bi bonding environment in the lattice sites. The result agrees with photoluminescence (PL) measurement which shows that the studied GaAs1-xBix films include local areas with higher Bi content, which contribute to PL but do not readily appear in x-ray diffraction (XRD). The measured and calculated Bi core-level shifts show also that Ga vacancies and Bi clusters are dominant defects.

Last updated on 2019-29-01 at 22:30