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arXiv · 1909.02397

Defect physics in $Yb^{3+}$-doped $CaF_2$ from first-principles calculation

Yun-Hyok Kye·Chol-Jun Yu·Un-Gi Jong·Chol-Nam Sin·Weiping Qin
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Abstract

Calcium fluoride has been widely used for light up-/down-conversion luminescence by accommodating lanthanide ions as sensitizers or activators. Especially, Yb-doped \ce{CaF2} exhibits unique defect physics, causing various effects on the luminescence. This makes it vital for high efficiency of devices to control the defect-clustering, but theoretically principal guidelines for this are rarely provided. Here we perform the first-principles study on defect physics in Yb-doped \ce{CaF2} to reveal the thermodynamic transition levels and formation energies of possible defects. We suggest that the fluorine rich growth condition can play a key role in enhancing the luminescence efficiency by facilitating the Yb-clustering and suppressing the defect quenchers in bulk. Detailed energetics of defect aggregation not only well explains the experimentally favored Yb-clustering but also presents $n$- or $p$-type doping method for the cluster control.

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Yun-Hyok Kye, Chol-Jun Yu, Un-Gi Jong, Chol-Nam Sin, Weiping Qin. 2019-08-23. Defect physics in $Yb^{3+}$-doped $CaF_2$ from first-principles calculation. https://arxiv.org/abs/1909.02397

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