| 초록 |
Two-dimensional (2D) materials which possess atomically thin layer and periodic network structure, have emerged as the new paradigm of materials with enormous potentials, ranging from flexible/stretchable electronics and optoelectronics to sensing, energy technology and biomedical applications. In order to fully realize the critical commercial applications that 2D materials in modern electronics, the development of adequate lithographic processing for 2D materials is necessary. In particular, due to the weak van der Waals interaction (adhesion) between the hydrophilic substrate and the hydrophobic 2D film, the directly deposited 2D material film easily peels off the parent substrate when the substrate is immersed in an aqueous developer during 2D film patterning or device fabrication. To solve the problem, novel process that uses a non-aqueous developer is required. Herein, we demonstrate an unprecedented and reliable new photolithographic process for large-area patterning of molybdenum disulfide (MoS2) films on both SiO2/Si and polymer substrates, as well as a lift-off of deposited metals on MoS2 films using an Irgacure 651-doped poly(methyl methacrylate) resist and a non-aqueous developer. To verify the feasibility of our process, the fabrication and device performance of MoS2 field effect transistors (FETs) are reported. We achieved mobility of 0.47 cm2/V·S and the on/off ratio of 105 from MOCVD grown MoS2 back-gate FET on SiO2/Si substrate. In addition, the electrical characteristic of top-gate FET fabricated on a polyimide substrate are also presented. The mobility is 1.40 cm2/V·S, the on/off current ratio is slightly lower but is still ＞103. Notably, this method is widely applicable to water-free processes, regardless of the substrate type in use. We believe that our study makes a contribution for fabrication of 2D materials based device, which can be applied to a variety of materials and conditions. |
