Multi‐level Nonvolatile Transistor Memory With Optical Rewritability Utilizing Reverse‐Bias P‐N Junction of Oriented Rod‐Like Organic Molecules

Abstract

Electret has been extensively utilized as a charge‐trapping layer in organic phototransistor memory applications; nevertheless, the intricate nature of the unique structural configuration posed challenges regarding manipulating device characteristics and performance. Research on understanding material‐driven electronic performance in single‐component phototransistor memory is insufficient. This study highlights the morphology‐dependent characteristics of phototransistor memory composed of a single‐component only, followed by the expansion of optical manipulability by introducing heterojunction. A combined approach involving crystallographic and the intrinsic transistor field‐effect is employed to illustrate the intricate balance that exists between intermolecular, intercrystalline, as well as the charge transfer at the conjugated core and the carriers confinement at the non‐conjugated region. Ultimately, a novel concept of single‐component phototransistor memory is introduced. Given the performance stability of the devices, the emphasis is placed on fully optical programming. The mechanisms of charge transfer and charge trapping effect at heterojunctions under illumination remain challenging to explain. Consequently, a simplified stacking design utilizing molecular systems has been created. A P‐N junction configuration is designed in the studied N‐type phototransistor memory, demonstrating enriched minority carriers to modulate the content of trapped charges and thus leading its memory state switching without applying additional gate bias.