Textured organic ferroelectric-based transistors as neuromorphic devices

突触和神经元是人脑的基本信息处理单位。模仿人脑为开发高能效的神经形态计算机提供了一个巨大的平台，这种计算机可以比当今能耗非常低的计算机更快地解决复杂问题。该项目支持开发基于有机半导体的高性能晶体管并将其应用于人工突触设备的研究和教育活动。有机半导体在吸收从紫外线到近红外的波长方面非常多才多艺，并在晶体管结构中将它们与铁电介质相结合，从而允许电和光子突触模仿生物突触的重要功能。该项目包括基础研究和应用研究，汇集了一个在设备物理、工程、材料和生物物理学方面具有专业知识的团队。在该项目期间，将对广泛的学生进行培训，该项目涉及为高中生开展电子和纳米孔实验的动手项目。作为高级实验室的一部分，将开发一项新的生物物理学实验，在那里，本科生将接触到一种获得诺贝尔奖的单分子方法学，该方法学有助于揭示神经元功能的潜在活动。该项目的科学目标是开发基于有机铁电晶体管的神经形态装置。与聚合物铁电介质相结合，有机场效应晶体管(FET)有望成为电突触和光子突触模拟生物突触重要功能的候选材料。该项目采用了一种综合的方法来开发操纵铁电相的新体系结构，包括用于降低有机铁电FET亚阈值摆幅和工作电压的负电容概念，使用新的光刻技术对金属接触进行图案化和势垒修改，以及研究电和光子突触。到目前为止，基于FET的光子突触主要依赖于氧化物半导体，而氧化物半导体在可调带隙能量方面用途较少。随着有机半导体中合适的带隙能量范围和有效的激子解离机制，有机FET结构中的织构极化铁电介质有望增加神经形态计算的动态范围。有机半导体的弛豫特性可以由铁电介质的极化状态来控制。此外，负电容有机FET的潜力为低能耗神经形态器件开辟了一条令人兴奋的道路。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Synapses and neurons are the fundamental information processing units of the human brain. Mimicking the human brain provides a vast platform for the development of energy-efficient neuromorphic computers, which could solve complex problems faster than today’s computers with very low energy consumption. This project supports research and educational activities for developing high performing transistors based on organic semiconductors and applying them in artificial synaptic devices. Organic semiconductors are extremely versatile for absorbing wavelengths from the ultraviolet to the near infrared and combining them with ferroelectric dielectrics in transistor architecture allows for both electrical and photonic synapses to emulate important functions of biological synapses. The project involves both fundamental and applied research by bringing together a team with expertise in device physics, engineering, materials, and biophysics. A broad range of students will be trained during the project, which involves conducting hands-on projects on electronics and nanopore experiments for high school students. A new biophysics experiment will be developed as part of the Advanced Laboratory, where undergraduate students will be exposed to a Nobel Prize winning single-molecule methodology that was instrumental in uncovering activities underlying neuron function. The scientific objective of the project is to develop organic ferroelectric transistor based neuromorphic devices. Combined with polymer ferroelectric dielectrics, organic field-effect transistors (FETs) are promising candidates for both electrical and photonic synapses to emulate important functions of biological synapses. The project takes an integrated approach of developing new architectures for manipulating the ferroelectric phase including the concept of negative capacitance for lowering the subthreshold swing and operating voltage in organic ferroelectric FETs, using novel lithography techniques for patterning and barrier modification of the metal contacts, and investigating both electrical and photonic synapses. Thus far, FET based photonic synapses have mainly relied on oxide semiconductors, which are less versatile in terms of tunable bandgap energies. Along with the range of suitable bandgap energies and effective exciton dissociation mechanisms in organic semiconductors, texture-poled ferroelectric dielectrics in organic FET architectures are promising for increasing the dynamic range for neuromorphic computing. The relaxation characteristics of organic semiconductors may be controlled by the polarization state of the ferroelectric dielectric. Furthermore, the potential of negative capacitance organic FETs opens an exciting avenue for low energy consumption neuromorphic devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.