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V. Melnik et al.
Fig. 7 XRD spectra of ZnO films, as-grown (ZnO as-grown) and processed either upon 450 °C
(a) or 600 °C (b) annealing for 30 min (ZnO + FA) or implanting with 100 keV Ar + ions (ZnO +
I) followed by annealing at 450 °C (a) or 600 °C (b) for 100 s (ZnO + I+RTA) or 30 min (ZnO +
I + FA)
This in turn suggests that the AZO film is highly doped at the interface. Therefore,
the AZO/Si junction is asymmetric with a thicker space charge region in the Si
substrate compared with that in the ZnO film. Then the capacitance is simply C
≈ ε Si /W, where ε Si is the dielectric constant of Si, and W is the total thickness of
the space charge region. At reverse bias, the capacitance depends only weakly on
the frequency. In turn, at forward bias, the free electrons in Si are captured at the
interface states thus decreasing the capacitance with increasing the frequency.
V. Melnik et al.
Fig. 7 XRD spectra of ZnO films, as-grown (ZnO as-grown) and processed either upon 450 °C
(a) or 600 °C (b) annealing for 30 min (ZnO + FA) or implanting with 100 keV Ar + ions (ZnO +
I) followed by annealing at 450 °C (a) or 600 °C (b) for 100 s (ZnO + I+RTA) or 30 min (ZnO +
I + FA)
This in turn suggests that the AZO film is highly doped at the interface. Therefore,
the AZO/Si junction is asymmetric with a thicker space charge region in the Si
substrate compared with that in the ZnO film. Then the capacitance is simply C
≈ ε Si /W, where ε Si is the dielectric constant of Si, and W is the total thickness of
the space charge region. At reverse bias, the capacitance depends only weakly on
the frequency. In turn, at forward bias, the free electrons in Si are captured at the
interface states thus decreasing the capacitance with increasing the frequency.