Journal
NANO LETTERS
Volume 14, Issue 8, Pages 4628-4633Publisher
AMER CHEMICAL SOC
DOI: 10.1021/nl501659n
Keywords
MoS2; scanning tunneling microscopy/spectroscopy; two-dimensional electronics; defects; atomic resolution imaging
Categories
Funding
- NSF [DMR 1207108]
- [DOE-FG02-99ER45742]
- Division Of Materials Research
- Direct For Mathematical & Physical Scien [1207108] Funding Source: National Science Foundation
Ask authors/readers for more resources
The discovery of graphene has put the spotlight on other layered materials including transition metal dichalcogenites (TMD) as building blocks for novel heterostructures assembled from stacked atomic layers. Molybdenum disulfide, MoS2, a semiconductor in the TMD family, with its remarkable thermal and chemical stability and high mobility, has emerged as a promising candidate for postsilicon applications such as switching, photonics, and flexible electronics. Because these rely on controlling the position of the Fermi energy (E-F), it is crucial to understand its dependence on doping and gating. To elucidate these questions we carried out gated scanning tunneling microscopy (STM) and spectroscopy (STS) measurements and compared them with transport measurements in a field effect transistor (FET) device configuration. This made it possible to measure the bandgap and the position of E-F in MoS2 and to track its evolution with gate voltage. For bulk samples, the measured bandgap (similar to 1.3 eV) is comparable to the value obtained by photoluminescence, and the position of E-F (similar to 0.35 eV) below the conduction band, is consistent with N-doping reported in this material. We show that the N-doping in bulk samples can be attributed to S vacancies. In contrast, the significantly higher N-doping observed in thin MoS2 films deposited on SiO2 is dominated by charge traps at the sample-substrate interface.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available