Resistive behavior of Ni thin film on a cylindrical PET monofilament with temperature for wearable computing devices

Abstract

Various types of temperature-sensing devices have become essential components for wearable computing devices these days. Meanwhile, plenty of temperature-sensing devices were researched and developed. This paper firstly introduces a Ni thin film-based resistive temperature sensing device on a cylindrical PET monofilament which has excellent flexibility and a simple fabrication process in room temperature. The structure of the Ni resistive temperature-sensing device is very simple due to the Ni thin film deposition by radio frequency (RF) magnetron sputtering which requires no pattern. The temperature coefficient of resistance (TCR) indicates the temperature sensitivity of the Ni resistive temperature-sensing device. By calculating the resistance from I-V curves, the TCR shows a constant value of 2.44 x 10(-3) degrees C-1. Even after a repetitive bending and washing process of the PET monofilament which we report for the first time, the TCR maintains a high value ranging from 1.52 x 10(-3) degrees C-1 to 3.13 x 10(-3) degrees C-1. The results demonstrate that the PET monofilament combined with the Ni thin film can be a good candidate for a resistive temperature-sensing device. (C) 2017 Elsevier B.V. All rights reserved.