High‐Yield Fabrication of Electrolyte‐Gated Transistors Based on Graphene Acetic Acid

ABSTRACT Liquid‐gated transistors (LGTs) are versatile devices for low‐power electronics, in‐field sensors, and neuromorphic devices. Among functionalized graphene‐based materials, graphene acetic acid (GAA) has been successfully integrated into LGTs as a prototypical solution‐processable 2D material with controlled surface chemistry and a conductivity of 1.8 mS/m. Like other liquid‐phase exfoliated 2D materials, the printing of GAA networks into micropatterns on arbitrary surfaces represents a major challenge. To overcome this limitation, we leverage a dielectrophoretic‐based approach to fabricate GAA films with an average thickness of 470 nm. Our fabrication strategy offers several advantages: (i) high reliability (i.e. ≈ 100% success rate out of more than 25 fabricated devices); (ii) small amount of active material required (< 30 µL of a 0.2 mg/mL of GAA), (iii) high spatial‐resolution (i.e. the deposition efficiency scales inversely with electrodes distance), and (iv) no further post‐processing steps. Our GAA‐based LGTs exhibit lower channel resistance (10–30 kΩ) than drop‐cast counterparts, negligible gate leakage current (10–50 nA), and modest hysteresis. Moreover, hole/electron mobility of 10 −1 cm 2 V −1 s −1 and a Dirac voltage close to −189 mV have been demonstrated. Furthermore, these devices exhibit a stable electrical response when exposed to air for 4 h and to continuous bias stress for 30 min.