摘要
We demonstrate an ultrasensitive strain gauge based on a discontinuous metal film with a record detection limit as low as 8.3 × 10^-6. Constructed by well-tunable crevices on the nanometer scale within the film, this gauge exhibits an ultrafast dynamic response to vibrations with a frequency range of 1 Hz to 10 kHz. More importantly, the temperature coefficient of resistivity （TCR） of the metal film is tunable owing to the cancellation effect caused by the possibility of tunneling across the nanoscale crevices （showing a negative temperature dependence） and the electron conduction within the metal islands （showing a positive temperature dependence）. Consequently, a nullified TCR is achievable when the crevice size can be precisely controlled. Thus, a fabrication strategy to precisely control the nanoscale crevices was developed in this study through the real-time tracking of the electrical conductivity during thermal evaporation. The ultrasensitive strain gauge with a tunable thermal drift introduces numerous opportunities for precision devices and wearable electronics with superior reliability.
We demonstrate an ultrasensitive strain gauge based on a discontinuous metal film with a record detection limit as low as 8.3 × 10^-6. Constructed by well-tunable crevices on the nanometer scale within the film, this gauge exhibits an ultrafast dynamic response to vibrations with a frequency range of 1 Hz to 10 kHz. More importantly, the temperature coefficient of resistivity （TCR） of the metal film is tunable owing to the cancellation effect caused by the possibility of tunneling across the nanoscale crevices （showing a negative temperature dependence） and the electron conduction within the metal islands （showing a positive temperature dependence）. Consequently, a nullified TCR is achievable when the crevice size can be precisely controlled. Thus, a fabrication strategy to precisely control the nanoscale crevices was developed in this study through the real-time tracking of the electrical conductivity during thermal evaporation. The ultrasensitive strain gauge with a tunable thermal drift introduces numerous opportunities for precision devices and wearable electronics with superior reliability.
基金
Acknowledgements This work was partially supported by Innovation Funding of HUST for International Collaborations （No. 2014ZZGH018）, Specialized Research Fund for the Doctoral Program of Higher Education （No. 20130142120089）, and National Natural Science Foundation of China （Nos. 51371084 and 91545131）.
