The copper element (Cu) substituted ZnO
with the common formula ZnO70/
Cux/ZnO70 (x = 20,
50, and 70 nm) was manufactured using ALD and
Dc magnetron sputtering techniques, as a function
of the concentration of Cu as interlayer. The effect
of the amount of Cu doped in ZnO on the character
and dielectric and impedance properties was evaluated.
Scanning electron microscopy (SEM) and grazing
incident X-ray diffraction (GIXRD) were used to
assess the microstructure of the prepared thin films
and to obtain grain size measurements. The dielectric
properties (ε′, ε″) and the real part of the complex
electric modulus (M) were studied as a function of
frequency and temperature. A strong dependence and
correlation between the dielectric properties and the
thickness of the Cu interlayer were investigated. The
electrical impedance at different temperatures exhibited
a single semicircle, indicating that the response
arose from a single capacitive element corresponding
to the grains. The conduction of grains and grain
boundaries is detected from a complex impedance
spectrum by fitting the Nyquist plot with an appropriate
electrical circuit. It was revealed that the increase
of the thickness of the Cu interlayer of the ZnO/Cu/
ZnO system leads to a high dielectric constant and
a low value of the real part of the complex electric
modulus, which are very good candidates for microwave
semiconductor devices and various microelectronic
applications.