Band alignment at interfaces of few-monolayer MoS2 with SiO2 and HfO2

[Display omitted] •Internal photoemission of electrons from 4- and 2-monolayer thick MoS2 is observed.•We found barrier heights for electrons at interfaces between MoS2 and SiO2 or HfO2.•Sensitivity of the barrier height to oxide composition indicates presence of dipoles. Internal photoemission of e...

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Bibliographic Details
Published in:Microelectronic engineering 2015-11, Vol.147, p.294-297
Main Authors: Afanas’ev, V.V., Chiappe, D., Huyghebaert, C., Radu, I., De Gendt, S., Houssa, M., Stesmans, A.
Format: Article
Language:English
Subjects:
Band offset
Electron affinity
Interface barrier
Internal photoemission
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Summary:[Display omitted] •Internal photoemission of electrons from 4- and 2-monolayer thick MoS2 is observed.•We found barrier heights for electrons at interfaces between MoS2 and SiO2 or HfO2.•Sensitivity of the barrier height to oxide composition indicates presence of dipoles. Internal photoemission of electrons from 4- and 2-monolayer thick MoS2 films prepared by sulphurization of metallic Mo on top of SiO2 or HfO2/SiO2 insulating stacks is detected. This enables determination of the energy position of the MoS2 valence band which is found to be at 4.1–4.2eV below the SiO2 conduction band. At the interface with HfO2, a barrier height of 3.7eV is found, corresponding to an increase of the electron affinity of MoS2 by ≈0.5eV as compared to the SiO2 case. This suggests the presence of interface charges (or dipoles) in the interfacial HfO2 layer.
ISSN:0167-9317
1873-5568
DOI:10.1016/j.mee.2015.04.106