Solution-Processed InAs Nanowire Transistors as Microwave Switches

The feasibility of using self?assembled InAs nanowire bottom?gated field?effect transistors as radio?frequency and microwave switches by direct integration into a transmission line is demonstrated. This proof of concept is demonstrated as a coplanar waveguide (CPW) microwave transmission line, where the nanowires function as a tunable impedance in the CPW through gate biasing. The key to this switching capability is the high?performance, low impedance InAs nanowire transistor behavior with field?effect mobility of ?300 cm2 V?1 s?1, on/off ratio of 103, and resistance modulation from only 50 ? in the full accumulation mode, to ?50 k? when the nanowires are depleted of charge carriers. The gate biasing of the nanowires within the CPW results in a switching behavior, exhibited by a ?10 dB change in the transmission coefficient, S21, between the on/off switching states, over 5–33 GHz. This frequency range covers both the microwave and millimeter?wave bands dedicated to Internet of things and 5G applications. Demonstration of these switches creates opportunities for a new class of devices for microwave applications based on solution?processed semiconducting nanowires.