Inkjet-printed MoS2-based field-effect transistors with graphene and hexagonal boron nitride inks

Abstract

Field-effect transistors (FETs) are powerful devices in the semiconducting electronics industry and their manufacturing forms the basis of countless electronic devices. Most contemporary FETs rely on inorganic materials, mainly silicon that uses conventional photolithography, etching, and deposition techniques in sophisticated and expensive clean-room environments. An alternative route to fabricating FETs is via inkjet printing that offers the possibility of mass production and working with additively manufactured, low-cost materials, to form high functionality devices with applications in a wide array of fields. Although the inkjet-printed electrode-based sensor is widely reported, the number of all inkjet-printed FETs is still limited. Here, the authors report the design, fabrication, and characterization of an all inkjet-printed FET. Two-dimensional layered materials, such as electrically conducting graphene, semiconducting molybdenum disulfide (MoS2), and dielectric-hexagonal boron nitride (hBN), were used to construct the printed FET on an Si/SiO2 substrate. Here, the authors also present the annealing temperature analysis of the drop-cast hBN ink, which provided a clear outlook toward the printed dielectric layer fabrication of the transistor. To have an idea of the leakage current of the FET, the authors inkjet-printed a simple capacitor device first with graphene and hBN inks, which was characterized by using the small-signal impedance technique, capacitance-frequency (C-F), and capacitance-voltage (C-V), where the change in C was measured from F ∼ 1 kHz up to 5 MHz. At low frequency, ∼1 KHz, the maximum capacitance ∼36 pF was found at 20 V.