Semiconductor nanowires have been studied owing to their excellent electrical properties. To implement an integrated system based on nanowires, well-aligned arrays of a nanowire are required for scalable and repeatable fabrication. In our previous results, a comparative study based on the current conduction mechanism of junctionless silicon nanowires was performed, and their characteristics were analyzed to offer a design guideline. Also, to implement a silicon-nanowire-based device, a top-down, wafer-level fabrication process of silicon-nanowire arrays on a flexible substrate was reported. The fabricated device consists of a voltage divider and a current driver in which silicon nanowires are used as a photodetector (PD) and field-effect transistors (FETs). The implemented silicon-nanowire-based circuit detects external light, generating a stimulation signal in proportion to the light intensity and transmitting the signal to a microelectrode. In this study, an analytical model based on a conduction mechanism of junctionless silicon nanowires is verified using a three-dimensional device simulator. Also, by applying the extracted electrical parameters of silicon-nanowire-based devices, the proposed photodetection circuit is simulated for the implementation of a photosensitive retinal prosthetic device. The results of this study can be applied to address novel silicon-nanowire-based neural stimulation devices and to guide the design of a high-resolution retinal prosthetic system.