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Dissertation Information
Title: Comparative Performance Analysis Of Multimodal Printed CNT Electronics: Extending To Nozzle-Free Approach
Program: Doctor of Philosophy in Electrical and Computer Engineering
Advisor: Dr. Kurtis Cantley, Electrical and Computer Engineering
Committee Members: Dr. Harish Subbaraman, Electrical Engineering (Co-Chair) and Dr. David Estrada, Materials Science and Engineering and Electrical and Computer Engineering
Abstract
Printed electronics is a rapidly growing field transforming electronics to flexible, bendable, stretchable, and lightweight form. Inkjet printer (IJP) is a widely used print modality limited by nozzle clogging. In this work, the effectiveness of a nozzle-free printing technique based on laser-generated focused ultrasound named shock-wave jet printing (SJP) is compared against IJP by printing nanomaterial , carbon nanotube (CNT) on SiO2/Si substrate. While multiple print passes were required to achieve optimal transistor performance with IJP printed CNT-TFTs compared to the current state-of-the-art devices reported in literature, the nozzle-free SJP printed CNT-TFTs showed the same performance with a single print pass. Here, maximum ION/IOFF of 10^6 and 10^4, and mobility of 23 and 135 cm2/V.s have been achieved for IJP and SJP printed CNT channels, respectively. Besides, for stored unsonicated CNT ink, SJP printed TFT showed a mobility of 10.8 cm2/V.s and ION/IOFF of 10^6 with single print pass while print attempts using same ink caused nozzle clogging in IJP. In subsequent study, top-gate CNT-TFTs with solution processed dielectric and gold (Au) electrodes on flexible Kapton substrate have been demonstrated where the CNT channels are either printed with an aerosol jet printer (AJP) or SJP. For this work, maximum ION/IOFF of 10^3 and 42, and maximum mobility of 5 and 1.27 cm2/V.s have been achieved for AJP and SJP printed CNT channels, respectively. Here, printed Au electrodes are used for the first time in printed CNT-TFTs which can sustain plasma treatment without becoming oxidized which could open a window for process optimization to improve device performance such as high current density, mobility, etc.
