Photoresponse Design in Metal Oxide Semiconductor TFTs toward Diverse Applications: Display Drivers, Photodetectors, and Optoelectronic Synapses

Different application domains impose diverse and often conflicting requirements on the optoelectronic performance of metal oxide semiconductor (MOS) thin-film transistors (TFTs). These varying demands present substantial challenges in the selection of TFT materials and the optimization of device performance. This study begins by examining three primary application areas for TFTs: display drivers, photodetectors, and optoelectronic synapses. A comparative analysis of the optoelectronic properties is conducted among various MOS TFTs fabricated by magnetron sputtering, including indium-gallium-zinc-oxide (IGZO, In/Ga/Zn = 1:2:1), indium-gallium-oxide (IGO, In/Ga = 1:1), indium-zinc-oxide (IZO, In/Zn = 1:1), indium oxide (In₂O₃), and zinc oxide (ZnO). The investigation reveals the significant impact of material selection on key performance metrics essential for these applications, such as photoresponse, the decay rate of photocurrent (<i>I</i>_ph), and negative bias illumination stress (NBIS). Additionally, a comprehensive summary of the applicable domains for each type of TFT is provided. The study also explores the correlation between activation energy (<i>E</i>_a) and TFT performance, indicating that higher <i>E</i>_a is associated with a stronger persistent photoconductivity (PPC) effect but poorer stability. Furthermore, the content of oxygen vacancy (<i>V</i>_O) shows a positive correlation with the decay rate of <i>I</i>_ph. Lastly, the photogenerated carrier lifetime (τ) is derived and compared among the five MOS materials, revealing the potential applications and performance characteristics of each in optoelectronic devices. The findings offer a nuanced understanding of the intrinsic relationships between material properties, defect states, and photoelectric performance, thereby guiding the selection and optimization of channel layer materials for specific application requirements.