Controllable Shifts in Threshold Voltage of Top‐Gate Polymer Field‐Effect Transistors for Applications in Organic Nano Floating Gate Memory

Abstract

Organic field‐effect transistor (FET) memory is an emerging technology with the potential to realize light‐weight, low‐cost, flexible charge storage media. Here, solution‐processed poly[9,9‐dioctylfluorenyl‐2,7‐diyl]‐co‐(bithiophene)] (F8T2) nano floating gate memory (NFGM) with a top‐gate/bottom‐contact device configuration is reported. A reversible shift in the threshold voltage (VTh) and reliable memory characteristics was achieved by the incorporation of thin Au nanoparticles (NPs) as charge storage sites for negative charges (electrons) at the interface between polystyrene and cross‐linked poly(4‐vinylphenol). The F8T2 NFGM showed relatively high field‐effect mobility (µFET) (0.02 cm2 V−1 s−1) for an amorphous semiconducting polymer with a large memory window (ca. 30 V), a high on/off ratio (more than 104) during writing and erasing with an operation voltage of 80 V of gate bias in a relatively short timescale (less than 1 s), and a retention time of a few hours. This top‐gated polymer NFGM could be used as an organic transistor memory element for organic flash memory.

Synthesis of Cyclopentadithiophene–Diketopyrrolopyrrole Donor–Acceptor Copolymers for High-Performance Nonvolatile Floating-Gate Memory Transistors with Long Retention Time

“…The number of Au NPs was determined from SEM image as shown in Figure S16b and, ∼2182 Au NPs were present within a 2.76 × 10 –9 cm 2 area. Therefore, we concluded that ∼1.26 electrons were trapped in one Au NP and this result is similar to reported paper . We could obtain reproducible writing and easing characteristics of memory devices with CDT–DPP–TVT by applying a gate bias.…”

Printed, Flexible, Organic Nano‐Floating‐Gate Memory: Effects of Metal Nanoparticles and Blocking Dielectrics on Memory Characteristics

“…The values of retention time of the NFGM devices with the bilayers of the PS/PMMA and PS/PVP dielectrics were determined to be more than 10 7 s and ≈10 4 s, respectively, by extrapolating the I d plots at the ON and OFF states. To the best of our knowledge, the retention testing reported here indicates that the better or comparable retention characteristics compared to the previously reported results from other organic NFGM devices 11, 28, 36…”

High‐Performance Nonvolatile Transistor Memories of Pentacence Using the Green Electrets of Sugar‐based Block Copolymers and Their Supramolecules

“…The initial curves of the three OFET memory devices exhibit the hysteresis characteristic in Figure with the threshold voltage ( V th ) in the forward scans of –2.0 V(MHPS1), –2.3 V(MHPS2), and –1.7 V(MHPS3), respectively. For comparison, the OFET device incorporated with the PS electret shows no hysteresis between the forward and backward scans, with the corresponding V th value of –6.8 V (Figure S2,Supporting Information), similar to that reported in the literature . The MHPS1–3 electret based devices possess more positive V th compared to that using the PS film, indicating the electron‐trapping ability by the hydroxyl groups of the MH blocks.…”