Impurity sublattice localization in ZnO revealed by Li marker diffusion.
A Yu Azarov1, K E Knutsen, P T Neuvonen
1Department of Physics, Centre for Material Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo, Norway.
Physical Review Letters
|May 18, 2013
Summary
Monitoring lithium diffusion reveals impurity sublattice localization in zinc oxide (ZnO). This finding clarifies doping mechanisms and impurity behavior in semiconductors, crucial for electronic and optical applications.
Area of Science:
- Materials Science
- Solid State Physics
- Semiconductor Physics
Background:
- Sublattice localization of impurities in compound semiconductors like zinc oxide (ZnO) critically influences their electronic and optical properties.
- Accurate determination of impurity site occupancy is essential for understanding semiconductor doping mechanisms and material performance.
Purpose of the Study:
- To demonstrate a method for revealing preferential sublattice occupation of impurities in ZnO by monitoring lithium diffusion.
- To elucidate the mechanisms behind impurity incorporation and their impact on lattice site occupancy.
Main Methods:
- Utilizing ion implantation to introduce various impurities into ZnO.
- Analyzing lithium diffusion profiles (depletion and pileup) to infer impurity sublattice localization.
- Conducting co-doping experiments (e.g., Cd+O, Mg+O) to investigate impurity interactions.
Main Results:
- Impurities like B, Mg, P, Ag, Cd, and Sb occupying the Zn sublattice create Li-depleted regions.
- Impurities such as N on O sites lead to Li pileups.
- Implanted oxygen atoms effectively block fast-diffusing zinc interstitials, acting as a filter.
Conclusions:
- Lithium diffusion serves as a sensitive probe for determining impurity sublattice localization in ZnO.
- The observed phenomena are explained by the generation of excess Zn and O interstitials based on impurity site occupancy.
- Understanding these mechanisms is vital for controlled doping and advanced semiconductor device design.
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