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Ionic Space‐Charge Depletion in Lithium Fluoride Thin Films on Sapphire (0001) Substrates |
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| Authors: | Chilin Li Xiangxin Guo Lin Gu Dominik Samuelis Joachim Maier |
| Affiliation: | 1. Max Planck Institute for Solid State Research, Heisenbergstra?e 1, D‐70569 Stuttgart, Germany;2. Key Laboratory of Transparent and Opto‐functional Inorganic Materials, Shanghai Institute of Ceramics (CAS), 1295 Ding Xi Road, Shanghai 200050, China;3. WPI Advanced Institute for Materials Research, Tohoku University, 2‐1‐1 Katahira, Aoba‐ku, Sendai 980‐8577, Japan |
| Abstract: | Lithium fluoride thin films with various thicknesses have been grown on c‐plane sapphire substrates by radio‐frequency sputtering. The thin films are granular with a preferential 111] orientation of the grains. Thickness‐dependent measurements allow the separation of bulk and interface conductions. The normalized conductance decreases linearly with decreasing LiF layer thickness with a negative extrapolated intercept. DC polarization, AC impedance spectroscopy and electromotive force measurement indicate depletion of lithium ion vacancies as majority charge carriers and hence a negative space‐charge potential. A generalized Mott–Schottky approach within the model of heterogeneous doping fully explains the entire boundary defect chemistry. |
| Keywords: | space charge depletion lithium fluoride thin films |