Electrolyte gated nanowire field-effect transistor for advanced control of thermoelectric functionalities

In the field of Iontronics - the technology of controlling electronic properties in materials by exploiting ionic motion in electrolytes - semiconductor nanowires are emerging as a promising material platform [1,2] naturally taking advantage of optimal features enabled by the use of electrolytes as gating media: strong capacitive coupling, intense electric fields and conformal gating geometry. In this frame, a fundamental concept is the electric double layer (EDL) forming the at electrolyte/nanowire interface, whose spatial extent of the order of the nanometer allows to provide gate dielectrics for nanowire-based devices with unprecedented performance.
In this talk, recent results on nanowire based EDL transistors will be reported. The effects of intense electric fields achieved by EDL gating allowing to modify the doping in semiconducting nanowires in a completely reversible way will be shown, as well as the effects on transport parameters such as carrier mobility [3]. Moreover, a novel device architecture exploiting electrolyte conformal gating will be reported: this allows to access simultaneously electrical and thermal transport [4] properties of a semiconductor nanostructure, and can be exploited for the effective modulation of the thermoelectric figure of merit ZT in nanowire-based thermoelectric generators [5].

Refs.:
[1] J. Lieb, V. Demontis, D. Prete et al., Ionic liquid gating of InAs nanowire-based field-effect transistors, Adv. Func. Mat., 29, 3, 2019.
[2] D. Prete et al., III-V semiconductor nanostructures and iontronics: InAs nanowire-based electric double layer field effect transistors, AIP Conf. Proc., 2145, 2019.
[3] D. Prete et al., Impact of electrostatic doping on carrier concentration and mobility in InAs nanowires, Nanotechnology, under review.
[4] M. Rocci, V. Demontis, D. Prete et al., Suspended InAs nanowire-based devices for thermal conductivity measurement using the method, JMEPEG 27, 6299-6305, 2018.
[5] D. Prete et al., Electrolyte gating enabling simultaneous electrical and thermal conductivity control on semiconductor nanowires, in preparation.

Fabio Taddei (9038) - fabio.taddei@nano.cnr.it
Stefan Heun (9472) - stefan.heun@nano.cnr.it