Electromechanical losses in carbon- and oxygen-containing bulk AlN single crystals
Autor: | Yuriy Suhak, Klaus Irmscher, Jürgen Wollweber, Carsten Hartmann, Andrea Dittmar, Holger Fritze, Ivan Gamov, Michal Schulz, Sebastian Schröder, Iurii Kogut, Matthias Bickermann, T. Straubinger |
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Rok vydání: | 2019 |
Předmět: |
Materials science
02 engineering and technology General Chemistry Activation energy Nitride Atmospheric temperature range 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Crystallographic defect Piezoelectricity 0104 chemical sciences Impurity Electrical resistivity and conductivity General Materials Science Charge carrier Composite material 0210 nano-technology |
Zdroj: | Solid State Ionics. 343:115072 |
ISSN: | 0167-2738 |
Popis: | Bulk single-crystalline aluminum nitride (AlN) is potentially a key component for low-loss high-temperature piezoelectric devices. However, the incorporation of electrically active impurities and defects during growth of AlN may adversely affect the performance of piezoelectric resonators especially at high temperatures. The electrical conductivity and electromechanical losses in bulk AlN single crystals are analyzed in the temperature range of 300–1200 K with respect to various contents of growth-related impurities in them. For AlN with [O]/[C] ≤ 1, an increase of electrical conductivity due to thermal activation of charge carriers in the temperature range of 850–1200 K has been observed and was determined to be a major contribution to electromechanical losses Q−1 rising up to maximum values of about 10−3 at 1200 K. As the oxygen content in AlN increased, the magnitude and the activation energy of high-temperature electrical conductivity increased. In oxygen-dominated AlN, two major thermally activated contributions to electromechanical losses were observed, namely, the anelastic relaxations of point defects at temperatures of 400–800 K and electrical conductivity at T > 800 K. |
Databáze: | OpenAIRE |
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