Affiliation:
1. Department of Electrical and Computer Engineering Inter‐University Semiconductor Research Center (ISRC) Seoul National University Seoul 08826 Republic of Korea
Abstract
Field‐effect transistor (FET)‐type pressure sensor offers excellent amplification and signal conversion functionality as a switching device, and it has the capability to integrate tactile sensors by constructing active‐matrix arrays with low crosstalk. However, conventional FET‐type pressure sensors either have a complex device layout with additional components, such as pressure‐sensitive elastomer, attached to the source/drain electrodes, or the method of modulating the gate dielectric can lead to dielectric breakdown and device failure. Additionally, the deformation of the elastomer limits response speed and causes differences in early and late response characteristics. In this article, a facile structure pressure‐sensing thin film transistor (TFT) that modulates the channel conductivity by cellulose/single‐wall carbon nanotube (SWCNT) composite is reported, ensuring a simple layout without damaging the device. The fabricated cellulose/SWCNT‐based pressure‐sensing TFT exhibits a change in the on/off current ratio from 2.75 × 103 to 2.0 × 104 in response to pressure with high linearity (R2 = 0.9935) and maintains durable performance over 2000 loading‐unloading cycles. Additionally, the sensor shows a fast response time of less than 8 ms. A practical concept of sensing circuits is demonstrated based on pressure‐sensing TFTs for integration into display driving circuits, enabling accurate pressure sensing using only the signal to drive the display.