We demonstrate, for the first time, the use of a solution-processed reduced graphene oxide (rGO) layer as a work function tunable electrode in vertical Schottky barrier (SB) transistors. The rGO electrodes were deposited by simple spray-coating onto the substrate. The vertical device structure was formed by sandwiching a N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) organic semiconductor between rGO and Al electrodes. By varying the voltage applied to the gate electrode, the work function of rGO and thus the SB formed at the rGO-PTCDI-C8 interface could be effectively modulated. The resulting vertical SB transistors based on rGO-PTCDI-C8 heterostructures exhibited excellent electrical properties, including a maximum current density of 17.9 mA/cm2 and an on-off current ratio >103, which were comparable with the values obtained for the devices based on a CVD-grown graphene electrode. The charge injection properties of the vertical devices were systematically investigated through temperature-dependent transport measurements. Charge injection was dominated by thermionic emission at high temperature. As the temperature decreased, however, impurity state-assisted hopping occurred. At low temperature and negative gate voltage, the reduced width of barrier induced by a high drain voltage yielded Fowler-Nordheim tunneling at the interface. The use of scalable solution-processed rGO as a work function tunable electrode in vertical SB transistors opens up new opportunities for realizing future large-area flexible two-dimensional materials-based electronic devices.
Bibliographical noteFunding Information:
This work was supported by the Center for Advanced Soft-Electronics funded by the Ministry of Science, ICT and Future Planning as Global Frontier Project (2013M3A6A5073177 and 2014M3A6A5060953). This work was also supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2017R1A2B2005790 and NRF-2017R1C1B2006789).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry