Temperature dependence of the EPR signal in ZnO
Ceramics based on zinc oxide doped with lithium was fabricated. It is shown that an increase in the lithium content in an amount up to 0.1% leads to a decrease in electrical conductivity, and then in the range up to 3% to its increase. The real and imaginary parts of the permittivity decrease with increasing lithium concentration over the entire range of measured frequencies (50 kHz - 3 MHz). Similarly, the signal of the EPR line with g-factor ~1.96 decreases. An analysis of the temperature dependence of the EPR signal intensity with a g factor of ~1.96 gives an activation energy of 0.06 eV, which practically coincides with the depth of shallow donors in ZnO. This makes it possible to identify the EPR signal with g-factor ~1.96 with oxygen vacancies.