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

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 cm2V−1s−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.