Multi-level non-volatile organic transistor-based memory using lithium-ion-encapsulated fullerene as a charge trapping layer

We report on multi-level non-volatile organic transistor-based memory using pentacene semiconductor and a lithium-ion-encapsulated fullerene (Li⁺@C₆₀) as a charge trapping layer. Memory organic field-effect transistors (OFETs) with a Si⁺⁺/SiO₂/Li⁺@C₆₀/Cytop/Pentacene/Cu structure exhibited a performance of p-type transistor with a threshold voltage (V_th) of −5.98 V and a mobility (μ) of 0.84 cm² V⁻¹ s⁻¹. The multi-level memory OFETs exhibited memory windows (ΔV_th) of approximate 10 V, 16 V, and 32 V, with a programming gate voltage of 150 V for 0.5 s, 5 s, and 50 s, and an erasing gate voltage of −150 V for 0.17 s, 1.7 s, and 17 s, respectively. Four logic states were clearly distinguishable in our multi-level memory, and its data could be programmed or erased many times. The multi-level memory effect in our OFETs is ascribed to the electron-trapping ability of the Li⁺@C₆₀ layer.