Figure 4.

(a) Small-signal ($100\mathrm{mV}$ and $10\mathrm{kHz}$) C-V measurements in dark and under different illumination levels. The inset highlights a crossover point between two regions where the capacitance of the device is dominated by the Schottky diode ($V<-0.25\mathrm{V}$) and the MOS capacitor $(V>-0.25\mathrm{V})$, respectively. (b) $\frac{1}{C^2}-V$ plot of the device under study.