Tailoring the Tunneling-Effect-Boosted Interfacial Charge Trapping via Effective Conjugation Length

Highly efficient charge injection and charge trapping stability of the tunneling layer are of desirable and practical importance to transistor memory applications. However, both of which can be contradictory to the nature properties of its material. It is herein demonstrated that lowering the energy mismatch of the tunneling layer by employing a longer conjugation length of the polymer can improve the charge injection efficiency, albeit the trapped charges will be easily diminished and finally losing its memory characteristics, and vice versa. To further elaborate and verify this concept, both materials are blended with distinct nature of properties as the tunneling layer in pentacene-based transistor devices. As the results, the device using 300 nm SiO₂ with optimum blending ratio displays a broad memory window of ≈77.6 V which is superior to the non-blended tunneling layer carrying appropriate energy levels and band gap energy, not to mention, revealing fast operation time (≈1 s), low driving voltage (≈20 V), long retention (>10⁴ s), and high switching stability over 50 cycles with on–off ratio of >10⁴. Most importantly, this finding shed insight into the design of tunneling materials for advancing organic transistor memory technologies based on tunneling-effect-boosted interfacial charge trapping.