| AVS 58th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Friday Sessions |
| Session GR+MS+EM-FrM |
| Session: | Graphene Device Physics and Applications |
| Presenter: | Yusuke Yamashiro, Osaka University, Japan |
| Authors: | Y. Yamashiro, Osaka University, Japan Y. Ohno, Osaka University, Japan K. Maehashi, Osaka University, Japan K. Inoue, Osaka University, Japan K. Matsumoto, Osaka University, Japan |
| Correspondent: | Click to Email |
Electric fields were applied to a bilayer graphene to generate a band gap using an ionic-liquid gate instead of the general top-gate structures. The ionic-liquid gate can apply higher electric field than other type of the gates because of its large capacitance and electric strength. In this abstract, the graphene layers were extracted from kish graphite by a mechanical exfoliation and were put on highly n-doped Si substrates covered with a 300-nm-thick SiO2 layer. Side-gate electrodes were patterned approximately 20 mm away from the channels. An ionic liquid (DEME-TFSI) was put on the bilayer graphene and the side-gate electrode. Electrical characteristics at 300 K revealed that the electrical double layer in the ionic-liquid, which works as a very thin insulator, had 200 times larger capacitance than a 300-nm-thick SiO2 layer. The thickness of electrical double layer was estimated to be 3.75 nm. In electric field dependence measurements, an increase in a sheet resistance of the bilayer grapheme channel was clearly observed with increasing the magnitude of electric field in bilayer graphene. On the other hand, the increase in the sheet resistance didn’t appear in the monolayer- and trilayer- graphene. That is why the increasing of the sheet resistance was caused by a band gap generated in ionic-liquid gated bilayer graphene by the electric field.