Semiconducting Carbon Nanotubes with Light-Driven Gating Behaviors in Phototransistor Memory Utilizing an N-Type Conjugated Polymer Sorting

Abstract

Semiconducting single-walled carbon nanotubes (s-SWNTs) have arisen a growing interest in field-effect transistors (FETs) due to their advantages, such as lower fabrication temperature, flexibility, and solution processing applicability, compared to traditional silicon-based FETs. In this study, diversifying the functionality of s-SWNT-based FETs is focused on, particularly emphasizing their use in nonvolatile photomemory applications. By selectively wrapping s-SWNT with n-type conjugated polymers (CPs), electron-trapping and photoresponsive capabilities are endowed in the device. After optimizing the structure and aggregating behavior of n-type CPs, a favorable supramolecular network comprising s-SWNT and CPs is formed and applied in phototransistor memory. Accordingly, the device exhibits a high memory ratio and window of 105 and 75.7 V, representing its remarkable charge-storage capabilities. In addition, the device demonstrates decent long-term stability over 104 s and multilevel memory behavior driven by the varied gate bias or accumulated light-gating periods. The proposed memory mechanism involves electrical writing and photoerasing processes with the existence of n-type CPs on s-SWNT, revealing the underlying principles of charge transfer between their heterojunction interfaces. Herein, this research contributes to developing advanced phototransistor memory, offering a promising avenue for future electronic applications.