Study Of A New Pressure Senor Device And Its Integration With Thin-Film Transistors

Transparent, elastic pressure sensors have recently received moreand more attentions as essential components of electronic andoptoelectronic devices that enhance human interaction or human-likesensing capabilities in robotic systems. However, it is quite challenging toachieve such devices of all the required properties including transparency,sensitivity and mechanical elasticity with simple and low cost processes.In this work, transparent stretchable capacitive pressure sensors weremade by laminating two stretchable conductive films together. Thesefilms were produced by embedding silver nanowires onto the surface ofbiocompatible polydimethylsiloxane (PDMS) elastomeric membraneswith low cost solution based processes, and present very low sheetresistance and good transparency.For the purpose of circuit and system applications, the integration ofthe capacitive pressure sensors with thin-film transistors (TFTs) wasfurther investigated. In this part, the operation mechanisms of TFTs werefirst introduced. Then the contact effects of TFTs, by using the method ofexperiments and device simulation, which was known to be influenced bythe channel length, drain voltage bias and the source/drain metal materials. Finally, considering the operation voltage requirement, lowoperation voltage solution processed oxide thin-film transistors werefabricated to integrate with the capacitive pressure sensor.The integration was achieved by lamination process to form anintegrated pressure sensor device. Current response to the pressure wasdirectly measured with the integrated structure, and the responsesensitivity can be improved by adjusting the gate voltage bias.