Enhanced Ultraviolet Photodetector Based on Thin-Film Transistor Incorporating Plasmonic Aluminum Nanoparticles and Nanohole Array: A Computational Study

Ultraviolet photodetectors (UVPDs) have gained significant attention due to their potential applications in various fields. Recently, advancements in electronic devices have enabled the use of thin-film transistors (TFTs) in UVPDs, due to their low-power consumption and ease of fabrication. Among the various UVPD architectures, zinc oxide (ZnO)-based TFTs are promising candidates for ultraviolet (UV) light absorption because of their wide direct bandgap of 3.4 eV. However, a key challenge of ZnO TFTs is their low efficiency, which degrades their responsivity and other critical UVPD parameters. In this study, spherical aluminum nanoparticles (AlNPs) were embedded within an active ZnO layer, and an aluminum nanohole (AlNH) array was employed as the source and drain electrodes. Embedded AlNPs enhanced free electron generation via the localized surface plasmon resonance (LSPR) in the UV spectrum. In addition, the AlNH array enables extraordinary optical transmission for irradiating the active layer and plasmonic enhancement to amplify electron generation. Under a light intensity of $1250~\mu $ W/cm2 and wavelength of 250 nm, output currents for the proposed UVPD structures are as follows: 1.5, 1.55, 1.6, and $2.3~\mu $ A for the bare TFT, AlNH array-based TFT, AlNPs-embedded TFT, and TFT incorporating both the AlNH array and AlNPs, respectively. The ZnO TFT UV sensor based on AlNH array and AlNPs demonstrated an output current 1.5 times higher than that of the bare ZnO TFT UV sensor.