Comparative dielectric analysis of Schottky diodes from the perspective of the high-dielectric interlayers (pure, N, S, Cu doped DLC) and light exposure

This study primarily aims to elucidate the impact of different interlayers employed in Schottky diodes (SDs) on their dielectric properties. A further aim of this study is to reveal the variation in the relevant dielectric properties with illumination. To this end, four SDs incorporating DLC, N-DLC, S-DLC, and Cu-DLC interlayers were produced via the electrochemical deposition method, and their impedance measurements were performed at ambient temperature and 1 MHz frequency value. Afterwards, the measurements were repeated under an illumination intensity of 100 mW/cm². The computed ${\epsilon }^{\prime }$, ${\epsilon }^{″}$ and tanδ values exhibit interlayer-dependent variations in both the depletion and accumulation regions. In the M* analysis, the M′–V plots show a gradual decrease, with a sharp decline in the depletion region, while the M″–V plots display a distinct peak in the same voltage range, corresponding to the relaxation process. On the other hand, the M″–M′ plots confirm a single relaxation process, with the arc radius varying depending on the interlayer type. Additionally, the SD with S-DLC interlayer exhibits the highest ${\sigma }_{\mathrm{ac}}$ conductivity, while phase angle values represent the capacitive traits of all the interlayers. Dielectric data indicate that illumination becomes effective in both depletion and accumulation regions. Notably, SDs incorporating DLC and Cu-DLC interlayers exhibit the highest illumination sensitivity. Overall, the noticeably high ${\epsilon }^{\prime }$ values of all SDs, compared to the conventional SiO₂, indicate an enhanced capacity for charge and energy storage, emphasizing the originality and potential of employing DLC, whether doped or undoped, as an interlayer in SDs.