Mixed Dimensional ZnO/WSe 2 Piezo-gated Transistor with Active Millinewton Force Sensing.

This work demonstrates a mixed-dimensional piezoelectric-gated transistor in the microscale that could be used as a millinewton force sensor. The force-sensing transistor consists of 1D piezoelectric zinc oxide (ZnO) nanorods (NRs) as the gate control and multilayer tungsten diselenide (WSe 2 ) as the transistor channel. The applied mechanical force on piezoelectric NRs can induce a drain-source current change (Δ I ds ) on the WSe 2 channel. The different doping types of the WSe 2 channel have been found to lead to different directions of Δ I ds . The pressure from the calibration weight of 5 g has been observed to result in an ∼30% I ds change for ZnO NRs on the p-type doped WSe 2 device and an ∼-10% I ds change for the device with an n-type doped WSe 2 . The outcome of this work would be useful for applications in future human-machine interfaces and smart biomedical tools.