Novel Field-Effect Schottky Barrier Transistors Based on Graphene-MoS2 Heterojunctions

• Published in: Scientific reports 2014-08, Vol.4 (1), p.5951-5951, Article 5951
• Main Authors: Tian, He, Tan, Zhen, Wu, Can, Wang, Xiaomu, Mohammad, Mohammad Ali, Xie, Dan, Yang, Yi, Wang, Jing, Li, Lain-Jong, Xu, Jun, Ren, Tian-Ling
• Format: Article
• Language: English
• Subjects: 639/301/357/918; 639/766/25; 639/925/918/1052; Humanities and Social Sciences; Mobility; Molybdenum; multidisciplinary; Science; Temperature effects; Theoretical analysis; Transistors; Voltage
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep05951

Recently, two-dimensional materials such as molybdenum disulphide (MoS 2 ) have been demonstrated to realize field effect transistors (FET) with a large current on-off ratio. However, the carrier mobility in backgate MoS 2 FET is rather low (typically 0.5–20 cm 2 /V·s). Here, we report a novel field-effect Schottky barrier transistors (FESBT) based on graphene-MoS 2 heterojunction (GMH), where the characteristics of high mobility from graphene and high on-off ratio from MoS 2 are properly balanced in the novel transistors. Large modulation on the device current (on/off ratio of 10 5 ) is achieved by adjusting the backgate (through 300 nm SiO 2 ) voltage to modulate the graphene-MoS 2 Schottky barrier. Moreover, the field effective mobility of the FESBT is up to 58.7 cm 2 /V·s. Our theoretical analysis shows that if the thickness of oxide is further reduced, a subthreshold swing (SS) of 40 mV/decade can be maintained within three orders of drain current at room temperature. This provides an opportunity to overcome the limitation of 60 mV/decade for conventional CMOS devices. The FESBT implemented with a high on-off ratio, a relatively high mobility and a low subthreshold promises low-voltage and low-power applications for future electronics.