Inks of dielectric h-BN and semiconducting WS2 for capacitive structures with graphene

We present dispersions of WS2 and h-BN using cyclohexanone and terpineol as the solvent to subsequently print prototype capacitive nanodevices. An all-inkjet-printing approach was used to print graphene-h-BN-graphene capacitors along with graphene-WS2-graphene structures. As the number of passes for inkjet printing the h-BN layer within graphene electrodes was increased, the leakage currents successively decreased. The capacitance-frequency (C-f) measurement data for the printed capacitor (with 40 passes of h-BN) within graphene electrodes showed that at ∼1 kHz, the maximum capacitance was ∼62 pF, and with increasing frequency, the capacitance value decreases. The inkjet printed graphene-WS2-graphene heterostructure devices were also constructed using horn tip sonication, where the C-f measurements revealed that C as high as ∼324.88 pF was attainable, which was largely frequency independent up to ∼20 kHz. This is in contrast with the h-BN layer integrated with graphene electrodes, where the measured C was more than ∼5 times lower over the range of frequencies tested and also exhibited a strong decay as frequency increased from 1 kHz.