Synthesis, Structure Characterization, and Quantum Theory Simulations of Polyimide-Au/PI/p-Si Polymer-Based Custom Photodiode

To achieve the intermediate step, an aromatic polyimide (API) soluble in polar solvents was synthesized via a polycondensation reaction. The synthesized API was characterized using some characterizations. Theoretical investigations were conducted on API polymer units utilizing density functional theory (DFT). The influence of the topological structure on the photodiode's performance was examined. The API material was deposited onto p-Si through the thermal evaporation method. The electrical parameters of the fabricated structure, including the ideality factor (n) (ranging from 2.5 to 4.5), barrier height (ΦB) (0.70–0.35 eV), and series resistance (Rs) (4.41–169.38 kΩ), were determined via I–V measurements at varying temperatures using the TE method, as well as Cheung and Norde functions. Furthermore, the photocurrent characteristics under different light intensities at room temperature and in dark conditions were analyzed. The evaluation of photodiode and photodetector-related measurements, along with photovoltaic parameters, indicates that this material has the potential to serve as an alternative for optoelectronic applications.