Electron Confinement at the Si/MoS2 Heterosheet Interface

• Published in: Advanced materials interfaces Vol. 3; no. 10
• Main Authors: Molle, Alessandro, Lamperti, Alessio, Rotta, Davide, Fanciulli, Marco, Cinquanta, Eugenio, Grazianetti, Carlo
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 23.05.2016; John Wiley & Sons, Inc
• Subjects: 2D silicon; MoS2; nanosheets; silicene; Transistors; van der Waal heterostructures
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.201500619

The electronic band line‐up between a uniform 2D silicon layer and a MoS2 substrate is shown to result in a distortion of the MoS2 bands. This effect is reflected in the admittance and electrical transport responses measured from the field‐effect transistor incorporating the Si/MoS2 heterosheet interface and fabricated from MoS2 multilayer flakes on SiO2/Si++ substrates. In particular, the gate modulation of the capacitance curve and the observation of a double‐peak feature in the transconductance profile make evidence of the built‐in of two active channels in the transistor: one at the MoS2/SiO2 interface and the other at the Si/MoS2 heterosheet interface. The emergence of a gate modulated conductive channel at the Si/MoS2 heterosheet interface is rationalized in terms of an effective electron accumulation at the Si/MoS2 interface that is consistent with the electronic band bending deduced from high‐resolution synchrotron radiation photoemission spectroscopy. A 2D silicon layer epitaxially grown on MoS2 is shown to result in a distortion of the MoS2 electronic bands in the proximity of the interface. This effect is responsible for the electron accumulation at the Si/MoS2 heterosheet interface which gives rise to an additional gate modulated electronic channel in the transistor response.