Sensitivity enhancement of a flexible MEMS strain sensor by a field effect transistor in an all organic approach

• Published in: Organic electronics Vol. 15; no. 11; pp. 3096 - 3100
• Main Authors: THUAU, D, ABBAS, M, CHAMBON, S, TARDY, P, WANTZ, G, POULIN, P, HIRSCH, L, DUFOUR, I, AYELA, C
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01-11-2014
• Subjects: Applied sciences; Electronics; Engineering Sciences; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; Micro and nanotechnologies; Micro- and nanoelectromechanical devices (mems/nems); Microelectronics; Micromechanical devices and systems; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Transistors; Performance evaluation; Electrical conductivity; Deflection; Micromachine; Strain sensing element; Cantilever beam; Drain current; Organic MEMS; Nanocomposite; Robustness; Cost lowering; Microelectromechanical device; Organic electronics; OFET; Gate voltage; Strain sensor; Measurement sensor; Strain sensors; Field effect transistor; Direct detection; Piezoresistive device; Response time; Economic aspect; Cost analysis; Nanostructured materials
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2014.08.063

We report a low-cost piezoresistive nanocomposite based organic micro electro mechanical system (MEMS) strain sensor that has been combined to an organic field effect transistor (OFET) with the objective of amplifying the sensitivity of the sensor. When the MEMS cantilever is strained by a mechanical deflection, the resulting variation of resistivity influences the gate voltage (VGS) of the OFET and, hence, changes the drain current (IDS) of the transistor. The present combination allows an enhancement of sensitivity to strain by a factor 3.7, compared to the direct detection of resistance changes of the nanocomposite. As a consequence, a low limit of detection of 24 ppm has been estimated in terms of strain transduction efficiency. Furthermore, the organic microsystem exhibits a short response time and operates reversibly with an excellent robustness.