Ali Rıza Deniz, Zakir Çaldıran
Abstract This work presents the fabrication and detailed characterization of a Schottky barrier photodiode with a nickel oxide (NiO) interlayer in the Au/NiO/p-Si/Al structure, aiming to surpass the performance limits of conventional silicon-based photodetectors. The wide bandgap (∼3.6 − 4.0 eV) and p-type carrier transport properties of NiO were exploited to optimize the conventional Au/p-Si interface. The device was successfully fabricated using low-cost and scalable methods, and its electrical and photoelectric performance were characterized at room temperature (T = 300 K) under irradiance intensities ranging from 0 mW/cm 2 to 100 mW/cm 2 . The Current-Voltage (I-V) analyses revealed that the diode exhibited significant deviations from the ideal Thermionic Emission (TE) theory: the ideality factor (n) increased from 1.52 in the dark to 4.34 under 100 mW/cm 2 , while the barrier height (Φ b ) decreased from 0.78 eV to 0.51 eV. This indicates that the series resistance (R s ) effect and the barrier height irregularities increased under light. Photodetector parameters confirmed that the device has an exponential response to light. The photosensitivity (S) and detectivity (D * ) values showed a continuous and exponential increase with increasing light intensity. The device achieved a competitive D * value of 1.75 × 10 8 Jones at the highest light intensity (100 mW/cm 2 ). This result proves that the Au/NiO/p-Si/Al structure maximizes the signal-to-noise ratio at high light levels and is a suitable candidate for high-sensitivity optical sensing applications.