cfaed Seminar Series
cfAED Seminar Series
Prof. Andras Kis , Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland
Single-Layer MoS2 – 2D Devices, Circuits and Heterostructures
09.09.2014 (Tuesday)
, 11:15 - 12:15
Barkhausenbuilding BAR II / 63a , Georg Schumann Straße 11 , 01187 Dresden
Prof. Andras Kis: Single-Layer MoS2 – 2D Devices, Circuits and Heterostructures
After quantum dots, nanotubes and nanowires, two-dimensional materials in the shape of sheets with atomic-scale thickness represent the newest addition to the family of nanoscale materials. Monolayer MoS2, a direct-gap semiconductor is a typical example of new graphene-like materials that can be produced using the adhesive-tape based cleavage technique. The presence of a band gap in MoS2 allowed us to fabricate transistors that can be turned off and operate with negligible leakage currents [1]. Furthermore, our transistors can be used to build simple integrated circuits capable of performing logic operations and amplifying small signals [2].
We have also successfully integrated graphene with MoS2 into heterostructures to form flash memory cells [3] that could be used to extend the scaling of this type of devices. Next, I will show photodetectors based on MoS2 that have a sensitivity surpassing that of similar graphene devices by several orders of magnitude. Incorporating MoS2 in van der Waals heterostructures can open the way to an extremely diverse range of materials where different layers cam be mixed and matched to different functionalities. This is not only limited to two-dimensional materials: classical 3D semiconductors with saturated dangling bonds can also be integrated with 2D semiconductors, as I will show on the example of p-Si/n-MoS2 heterostructures that behave as diodes and can be used to achieve light emission and energy harvesting in a broad energy range [4].
[1] B. Radisavljevic et al., Nat. Nanotechnol. 6, 147 (2011).
[2] B. Radisavljevic, M. B. Whitwick and A. Kis, ACS Nano 5, 9934 (2011).
[3] S. Bertolazzi, D. Krasnozhon and A. Kis, ACS Nano 7, 3246 (2013).
[4] O. Lopez-Sanchez et al., ACS Nano (2014).