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theses

Much research to date has focused on synthesizing new polymers or improving existing polymers, in order to overcome the limits of the conventional organic thin-film transistor (OTFT): (1) A rather low channel carrier mobility (< 20 cm²V^-1s^-1 typically) requires a power supply voltage well above 2 V for a reasonable on-/off-current ratio (> 10⁵); (2) The formation of a relatively poor-quality interface between the polymeric channel and gate insulator induces large off-state leakage current well above 10^-13 A; (3) Asymmetric pairs of n- and p-type OTFTs result in noncomplementary switching. All these would affect the overall power consumption at the transistor, circuit, and system levels. This doctoral dissertation proposes and demonstrates radically-different, organic microelectromechanical (MEM) relays, in order to overcome such limits and hence enable efficient implementation of portable and/or wearable large-area electronics for the internet of things requiring ultralow-power operation, structural flexibility, visual transparency, and low-cost/-temperature processing. Firstly, a polymer-based low-thermal-budget surface-micromachining process is developed to implement organic relay prototypes (comprising multiple or single input/output terminals). Fabricated relays exhibit unique I-V characteristics including immeasurably-low off-state leakage current, abrupt transitions to the on-/off-state with an input voltage swing less than 60 mV for a decade change in output current, a relatively high on/off current ratio well above 10⁵, and complementary switching behavior and can endure a finite number of hot- and cold-switching cycles. Secondly, the effects of humidity, temperature, and low-surface-energy contacting electrodes materials on switching characteristics (such as hysteresis voltages and on-state resistance) are investigated. Thirdly, basic Boolean operations including AND, OR, and XOR and logic functions (e.g., carry bit generation for four inputs) are demonstrated using a multi-input/-output relay.

ETD_8042

Ph.D.

Includes bibliographical references

by Yanbiao Pan

doi:10.7282/T3QR512D

ETD doctoral

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