Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 33: Poster Session III
HL 33.16: Poster
Mittwoch, 14. März 2018, 17:30–19:30, Poster F
Instability of the Sb vacancy in GaSb — •Natalie Segercrantz1,2, Jonatan Slotte2, Filip Tuomisto2, Kenichiro Mizohata3, and Jyrki Räisänen3 — 1Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Germany — 2Department of Applied Physics, Aalto University School of Science, Finland — 3Department of Physics, University of Helsinki, Finland
The narrow-gap semiconductor GaSb can be used in various optoelectronic devices. Undoped, GaSb is of p-type and the Ga antisite and the Ga vacancy have been shown to be responsible for the residual hole concentration. Self-diffusion experiments in GaSb have revealed another unusual asymmetry of GaSb. The Ga atom was found to diffuse three orders of magnitude faster in the material than the Sb atom. The Sb vacancy has been proposed to be unstable, exchanging sites with a neighboring Ga atom. This mechanism would enhance Ga diffusion due to the increased Ga vacancy defects while at the same time suppressing Sb diffusion.
We have studied the instability of the Sb vacancy by irradiating undoped, p-type GaSb and performing positron annihilation spectroscopy in the temperature interval 35-300 K. The Sb vacancy is shown to be unstable above temperatures of 150 K and undergoes a transition resulting in a Ga vacancy and a Ga antisite leading to a further increase in the acceptor-type defect distribution in proton irradiated material. The activation energy of this transition is determined to be 0.6 eV ± 0.1 eV. Our results prove that the instability of the Sb vacancy in GaSb has a profound role on the native defect distribution in GaSb.