Split Ga vacancies

We have applied positron annihilation spectroscopy to study a wide range of β-Ga2O3bulk crystals and thin films with various doping levels. The Doppler broadening of the 511 keV positron-electron annihilation line exhibits colossal anisotropy compared to other three-dimensional crystalline semiconductors. State-of-the-art theoretical calculations of the positron characteristics in the β-Ga2O3lattice reveal that the positron state is effectively 1-dimensional, giving rise to strong anisotropy. Strongly relaxed split Ga vacancies are found to exhibit even stronger anisotropy and to dominate the positron annihilation signals in almost all experiments. The evidence leads to the conclusion that split Ga vacancies are abundant, with concentration of 1018 cm-3 or more, in β-Ga2O3samples irrespective of conductivity.

Description

Keywords

Compensation, Defect, Gallium oxide, positron annihilation spectroscopy, Vacancy

DOI

10.1117/12.2585462

Citation

Tuomisto , F , Karjalainen , A & Makkonen , I 2021 , Split Ga vacancies : Abundant defects in β-Ga 2 O 3 . in D J Rogers , D C Look & F H Teherani (eds) , Oxide-Based Materials and Devices XII . , 2585462 , Proceedings of SPIE - The International Society for Optical Engineering , vol. 11687 , SPIE , Oxide-Based Materials and Devices , Virtual, Online , United States , 06/03/2021 . https://doi.org/10.1117/12.2585462

Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-202111019920

Collections

[article-cris] Perustieteiden korkeakoulu / SCI

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