Piezoelectric potential gated field-effect transistor based on a free-standing ZnO wire.
We report an external force triggered field-effect transistor based on a free-standing piezoelectric fine wire (PFW). The device consists of an Ag source electrode and an Au drain electrode at two ends of a ZnO PFW, which were separated by an insulating polydimethylsiloxane (PDMS) thin layer. The working principle of the sensor is proposed based on the piezoelectric potential gating effect. Once subjected to a mechanical impact, the bent ZnO PFW cantilever creates a piezoelectric potential distribution across it width at its root and simultaneously produces a local reverse depletion layer with much higher donor concentration than normal, which can dramatically change the current flowing from the source electrode to drain electrode when the device is under a fixed voltage bias. Due to the free-standing structure of the sensor device, it has a prompt response time less than 20 ms and quite high and stable sensitivity of 2%/microN. The effect from contact resistance has been ruled out.
Fei
Peng
P
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Yeh
Ping-Hung
PH
Zhou
Jun
J
Xu
Sheng
S
Gao
Yifan
Y
Song
Jinhui
J
Gu
Yudong
Y
Huang
Yanyi
Y
Wang
Zhong Lin
ZL