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

Abstract

The effects of using a blocking dielectric layer and metal nanoparticles (NPs) as charge‐trapping sites on the characteristics of organic nano‐floating‐gate memory (NFGM) devices are investigated. High‐performance NFGM devices are fabricated using the n‐type polymer semiconductor, poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} (P(NDI2OD‐T2)), and various metal NPs. These NPs are embedded within bilayers of various polymer dielectrics (polystyrene (PS)/poly(4‐vinyl phenol) (PVP) and PS/poly(methyl methacrylate) (PMMA)). The P(NDI2OD‐T2) organic field‐effect transistor (OFET)‐based NFGM devices exhibit high electron mobilities (0.4–0.5 cm2 V−1 s−1) and reliable non‐volatile memory characteristics, which include a wide memory window (≈52 V), a high on/off‐current ratio (Ion/Ioff ≈ 105), and a long extrapolated retention time (>107 s), depending on the choice of the blocking dielectric (PVP or PMMA) and the metal (Au, Ag, Cu, or Al) NPs. The best memory characteristics are achieved in the ones fabricated using PMMA and Au or Ag NPs. The NFGM devices with PMMA and spatially well‐distributed Cu NPs show quasi‐permanent retention characteristics. An inkjet‐printed flexible P(NDI2OD‐T2) 256‐bit transistor memory array (16 × 16 transistors) with Au‐NPs on a polyethylene naphthalate substrate is also fabricated. These memory devices in array exhibit a high Ion/Ioff (≈104 ± 0.85), wide memory window (≈43.5 V ± 8.3 V), and a high degree of reliability.

Controllable Threshold Voltage in Organic Complementary Logic Circuits with an Electron-Trapping Polymer and Photoactive Gate Dielectric Layer

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Medium band gap polymer based solution-processed high-κcomposite gate dielectrics for ambipolar OFET

“…The inset in figure 4 demonstrates that static dielectric constants measured at 100 Hz increase with the increasing concentration of Ta 2 O 5 . The obtained dielectric constant value of 3.6 for pure PMMA films is in very good agreement with the literature [26].…”

Synaptic organic transistors with a vacuum-deposited charge-trapping nanosheet

“…1c,d and Supplementary Fig. S2 ), we obtained a continuous and smooth Al sheet, in contrast to the previous reports where a-few-nm thin evaporated Al often appeared as nanoparticles or islands 25 26 . Two-dimensional (2-D) energy-dispersive X-ray spectroscopy (EDS), conducted on the cross-section of the Al SFG, also showed the formation of a continuous Al band along the PMMA surface in conjunction with a direct proof of oxidation ( Fig.…”