An organic ambipolar charge trapping non-volatile memory device based on double heterojunctions

Zhang, Peng; Jacques, Emmanuel; Pichon, Laurent; Bonnaud, Olivier

doi:10.1016/j.tsf.2022.139458

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…The insets in Figure g show magnified figures of areas with dashed lines. Compared to recently published floating gate memories, our on/off ratio and storage state performance is superior (Figure h). − In addition, both n- and p-type memories have excellent retention properties; after the V CG pulse is removed, these 16 states remain distinct for at least 2000 s, as shown in Figure b,e (full experimental data are shown in Figure S9). Subsequently, we theoretically predicted the programmed/erased state ratio (largest/lowest resistance ratio), as shown in Figure S10, and found that the ratio of 10 3 and 10 2 corresponds to the hole and electron resistance after 10 years.…”

Section: Resultsmentioning

confidence: 66%

Reconfigurable Artificial Synapse Based on Ambipolar Floating Gate Memory

Yao

Huang

et al. 2023

ACS Appl. Mater. Interfaces

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Artificial synapse networks capable of massively parallel computing and mimicking biological neural networks can potentially improve the processing efficiency of existing information technologies. Semiconductor devices functioning as excitatory and inhibitory synapses are crucial for developing intelligence systems, such as traffic control systems. However, achieving reconfigurability between two working modes (inhibitory and excitatory) and bilingual synaptic behavior in a single transistor remains challenging. This study successfully mimics a bilingual synaptic response using an artificial synapse based on an ambipolar floating gate memory comprising tungsten selenide (WSe 2 )/ hexagonal boron nitride (h-BN)/ molybdenum telluride (MoTe 2 ). In this WSe 2 /h-BN/MoTe 2 structure, ambipolar semiconductors WSe 2 and MoTe 2 are inserted as channel and floating gates, respectively, and h-BN serves as the tunneling barrier layer. Using either positive or negative pulse amplitude modulations at the control gate, this device with bipolar channel conduction produced eight distinct resistance states. Based on this, we experimentally projected that we could achieve 490 memory states (210 hole-resistance states + 280 electron-resistance states). Using the bipolar charge transport and multistorage states of WSe 2 /h-BN/MoTe 2 floating gate memory, we mimicked reconfigurable excitatory and inhibitory synaptic plasticity in a single device. Furthermore, the convolution neural network formed by these synaptic devices can recognize handwritten digits with an accuracy of >92%. This study identifies the unique properties of heterostructure devices based on two-dimensional materials as well as predicts their applicability in advanced recognition of neuromorphic computing.

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Section: Resultsmentioning

confidence: 66%

Reconfigurable Artificial Synapse Based on Ambipolar Floating Gate Memory

Yao

Huang

et al. 2023

ACS Appl. Mater. Interfaces

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“…基于电化学和热力学性质测试结果, 验证了 3Ph-TrH 不仅具有优异的化学和热力学稳定性, 且具有合适的最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO) 能级, 利于空穴和电子的注入, 进一步制备了基于纯 3Ph-TrH 材料作为电荷捕获层的 OFET 存储器. 结果表明该器件可以实现双极性电荷存储, 空穴存储和电子存储窗口分别为 31.2 和 11.6 V. 为了进一步优化器件, 利用小分子掺杂聚合物方法改善薄膜形貌提高器件的稳定性 [16,[26][27][28][29] , 进一步制备了基于 3Ph-TrH 与 PS 掺杂体系 [V(3Ph-TrH)∶V(PS)＝1∶10)作为电荷捕获层的浮栅型 OFET 存储器. 测试结果显示, 基于 3Ph-TrH/PS 作为电荷捕获层的器件相比基于 3Ph-TrH 作为电荷捕获层的器件, 其稳定性和耐受性明显提高, 在 10000 s 维持时间测试后该器件的电流开关比还能维持在 1.1×10 3 .…”

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Ambipolar Organic Field Effect Transistor Memory Based on H-Type Fluorene-Based Small Molecule

Liu,

Chen,

Shao

et al. 2023

Acta Chimica Sinica

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A small organic molecule 3Ph-TrH with a rigid structure was designed with π-bridge thienyl and fluorenyl groups as hole trapping sites and the fluorenyl and phenyl units as electron trapping sites according to steric hindrance. Then, the floating gate type organic field-effect transistor (OFET) memories based on this small organic molecule through solution processing were fabricated. The experimental results show that there is a hole storage window of 31.2 V and an electron storage window of 11.6 V in this device, exhibiting ambipolar charge storage based on a single small molecule material. To improve the stability of the device, a floating-gate OFET memory based on 3Ph-TrH with polystyrene (PS)-doped film was further prepared. The test results show that the device is equipped with better device stability and tolerance than those based on 3Ph-TrH as a single-component charge trapping layer. After 10000 s of retention times test, ON/OFF current ratio of the device can still be maintained at 1.1×10 3 , only reduced by an order of magnitude. This work can provide an idea for the preparation of a new type of OFET memory with ambipolar storage. Keywords steric hindrance; fluorene-based small molecule material; charge trapping layer; ambipolar charge storage; floating gate type organic field-effect transistor (OFET) memory 1 引言有机场效应晶体管(OFET)存储器由于其低成本、易加工、高密度信息存储、非破坏性读取、易与电路集成等诸多优点 [1][2][3][4][5][6] , 得到广泛关注. 其中, 通过电荷捕获层对电荷的俘获与释放实现对信息存储的 OFET 存储器, 成为近年来的研究热点之一 [7][8][9][10] . 目前, 可以充当电荷捕获层的材料可以大体将其分为三类: 有机小分子材料 [3] 、聚合物材料 [11] 、无机材料 [12] . 这当中有机小分子材料因具有分子量可控、合成步骤简易、易于纯化等优势, 而受到研究者的青睐 [10,[13][14] . 但目前大部分已报道的小分子表现出单极性存储 [3] , 只有少数可以通过单一小分子组分实现双极性电荷存储 [15][16][17] . 2018 年, 解令海课题组 [18] 报道了基于 D-A 型小分子 TPA(PDAF) 3 单组分的 OFET 存储器, 其中三苯胺和位阻型氮杂芴单元分别作为空穴和电子的存储位点, 并利用芴基 9-位共轭打断实现对存储电荷的阻挡, 表现出双极性电荷存储达到

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Surmounting Erase-Operation Limit in Organic Charge-Trap Memories by Fine Tuning Electron Injection at Semiconductor/Heterobimetallic Electrode Contacts

Kim,

Kwon

et al. 2024

ACS Appl. Mater. Interfaces

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Heterobimetallic systems (HBS), known for their ability to facilitate the versatile design of surface workfunctions, offer significant potential as an electron-injection electrode layer for organic semiconductors. In this paper, we propose a universal and effective strategy to overcome the limitations of the erase operation in charge-trap memory with a small-bandgap organic semiconductor or diketopyrrolopyrrole-quaterthiophene-conjugated polymer (PDPP4T) by utilizing HBS-based source/drain (SD) electrodes. Conventional gold SD electrodes restrict electron injection into the PDPP4T layer during the electrical erase operation and impose a lower limit on the erasing voltage required for full threshold-voltage recovery. The HBS SD electrodes with an upshifted Fermi level toward the lowest unoccupied molecular orbital level of PDPP4T enhanced electron injection during an electrical erase operation, reducing the erasing voltage and achieving a balance between programming and erasing voltages. In addition, an asymmetric SD structure was employed for preventing a decrease in the on-state drain current while maintaining an optimal erase operation.

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An organic ambipolar charge trapping non-volatile memory device based on double heterojunctions

Cited by 3 publications

References 27 publications

Reconfigurable Artificial Synapse Based on Ambipolar Floating Gate Memory

Reconfigurable Artificial Synapse Based on Ambipolar Floating Gate Memory

Ambipolar Organic Field Effect Transistor Memory Based on H-Type Fluorene-Based Small Molecule

Surmounting Erase-Operation Limit in Organic Charge-Trap Memories by Fine Tuning Electron Injection at Semiconductor/Heterobimetallic Electrode Contacts

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