التفاصيل البيبلوغرافية
| العنوان: |
Doping efficiency and electron transport in Al-doped ZnO films grown by atomic layer deposition. |
| المؤلفون: |
Mošková, A., Moško, M., Precner, M., Mikolášek, M., Rosová, A., Mičušík, M., Štrbík, V., Šoltýs, J., Gucmann, F., Dobročka, E., Fröhlich, K. |
| المصدر: |
Journal of Applied Physics; 7/21/2021, Vol. 130 Issue 3, p1-14, 14p |
| مصطلحات موضوعية: |
ATOMIC layer deposition, ELECTRON donors, ELECTRON transport, ZINC oxide films, DOPING agents (Chemistry), TRANSPORT theory, ELECTRON traps |
| مستخلص: |
Transparent conducting Al -doped ZnO films were grown by atomic layer deposition (ALD). Al -doping was introduced by inserting 1 A l 2 O 3 cycle per 28 ZnO cycles. The x-ray photoelectron spectroscopy showed that the density of the Al donors is 2 × 10 21 – 3 × 10 21 cm − 3 , while the Hall-effect measurements showed a ten times lower electron density. This low doping efficiency is a well-known inherent problem of the ALD method, and we wanted to explain its origin. We have found that the electron density is reduced by electron traps at the grain surface; however, the effect was too weak to explain the low doping efficiency. Therefore, the mechanism of the A l 2 O 3 doping was analyzed. We have proposed that each A l 2 O 3 molecule ideally provides two single-electron Al donors accompanied by one Zn vacancy, which acts as a two-electron acceptor. This would cause a perfect compensation; however, the compensation is in reality not perfect, which results in weakly efficient doping. Calculations also showed that each Zn vacancy creates a bound pair with an Al donor. To verify our doping model experimentally, it was inserted into the metallic transport theory and compared with the electron transport measurements. A good agreement was found for a broad range of experimental conditions. In the regime of weak localization, the conductivity showed the temperature dependence σ (T) = a + b T 3 / 4 , which is a signature of weak localization and electron–electron scattering in a 3D dirty metal. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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