Effect of an ITIC non-fullerene interlayer on electrical properties and external quantum efficiency of Al/ZnO/ p -Si Schottky photodiodes

Metal-semiconductor (MS) heterojunctions are one of the main components of today’s technology. In the production of metal-semiconductor heterojunctions; metal oxides, insulators or polymers are inserted as interlayers between metal and semiconductor to ameliorate the durability, stability and efficiency of heterojunctions. By improving their durability, stability and efficiency through the use of ITIC as an interlayer material, the performance of these devices can be enhanced. By adding ITIC to the ZnO interlayer, ITIC: ZnO layer heterojunctions applications were carried out in this study. ITIC, a nonfullerene material, is employed as an electron acceptor material in organic solar cells. The ITIC:ZnO composite layer in our study was grown on Si substrates using spin coating method. Subsequently, Al/ZnO/ p -Si and Al/ITIC:ZnO/ p -Si heterojunctions were produced by physical vapor deposition method and the electrical properties of the produced devices were characterized. In these characterizations, current-voltage measurements were performed in the dark and under various light power illumination intensities ranging from 20 to 100 mW/cm 2 . From the current-voltage characteristics, various electrical parameters were calculated. While the ideality factor values for Al/ZnO/p-Si were found to be 7.55 and 7.73, it was found as 6.83 and 6.65 for ITIC-doped photodiode using thermionic emission and Cheung models, respectively. The barrier height values for Al/ZnO/p-Si were 0.62 eV, 0.64 eV and 0.64 eV, while the same values were found as 0.60 eV, 0.63 eV and 0.61 eV for Al/ITIC:ZnO/p-Si using the thermionic emission, Cheung and Norde models, respectively. From current transient measurements, photosensitivity, specific detectivity and responsivity were calculated as optoelectronic parameters. Moreover, the heterojunctions demonstrated high external quantum efficiency with the addition of ITIC. According to the results, ITIC component is functional for photodiode and photodetector applications.