The temperature dependent negative dielectric constant phenomena of Au/n–GaAs structure with CZO interfacial layer

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In this study, the copper-doped (wt 3%) ZnO (CZO) thin film was deposited on n–type (100)–oriented GaAs substrate with the RF sputtering system and this film was annealed at 600 °C. The dielectric parameters such as dielectric constant ( $${\varepsilon }^{{\prime}}$$ ), dielectric loss ( $$\varepsilon^{ \prime \prime}$$ ), dielectric loss tangent ( $$\mathrm{tan}\delta $$ ), real ( $${M}^{{\prime}}$$ ) and the imaginary ( $$M^{\prime \prime}$$ ) part of the electric modulus, and ac conductivity ( $${\sigma }_{ac}$$ ) of Au/n–GaAs MOS structure with CZO thin film were examined in the temperature range of 200–380 K by 30 K steps. The variations of these parameters depending on the voltage were also discussed in the range of 1.5 V to 3.0 V by step 0.5 V. Dielectric constant has been studied in detail in three different temperature ranges as low (200 – 260 K), medium (290 K), and high (300 – 380 K). While the dielectric constant takes positive values for the low and medium temperature range in the forward bias voltage region, it takes negative values for the high temperature region. As a result of this study, negative dielectric constant behavior was observed for high temperature values.