Ti-A nd Fe-related charge transition levels in β-Ga 2 O 3

Christian Zimmermann*, Ymir Kalmann Frodason, Abraham Willem Barnard, Joel Basile Varley, Klaus Irmscher, Zbigniew Galazka, Antti Karjalainen, Walter Ernst Meyer, Francois Danie Auret, Lasse Vines

*Corresponding author for this work

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Abstract

Deep-level transient spectroscopy measurements on β-Ga 2 O 3 crystals reveal the presence of three defect signatures labeled E 2 a, E 2 b, and E 3 with activation energies at around 0.66 eV, 0.73 eV, and 0.95 eV below the conduction band edge. Using secondary ion mass spectrometry, a correlation between the defect concentration associated with E 3 and the Ti concentration present in the samples was found. Particularly, it is found that E 3 is the dominant Ti-related defect in β-Ga 2 O 3 and is associated with a single Ti atom. This finding is further corroborated by hybrid functional calculations that predict Ti substituting on an octahedral Ga site, denoted as Ti GaII, to be a good candidate for E 3. Moreover, the deep level transient spectroscopy results show that the level previously labeled E 2 and attributed to Fe substituting on a gallium site (Fe Ga) consists of two overlapping signatures labeled E 2 a and E 2 b. We tentatively assign E 2 a and E 2 b to Fe substituting for Ga on a tetrahedral or an octahedral site, respectively.

Original languageEnglish
Article number072101
Number of pages5
JournalApplied Physics Letters
Volume116
Issue number7
DOIs
Publication statusPublished - 18 Feb 2020
MoE publication typeA1 Journal article-refereed

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    Zimmermann, C., Frodason, Y. K., Barnard, A. W., Varley, J. B., Irmscher, K., Galazka, Z., ... Vines, L. (2020). Ti-A nd Fe-related charge transition levels in β-Ga 2 O 3. Applied Physics Letters, 116(7), [072101]. https://doi.org/10.1063/1.5139402