51 research outputs found
Investigating laser induced phase engineering in MoS2 transistors
Phase engineering of MoS2 transistors has recently been demonstrated and has
led to record low contact resistances. The phase patterning of MoS2 flakes with
laser radiation has also been realized via spectroscopic methods, which invites
the potential of controlling the metallic and semiconducting phases of MoS2
transistors by simple light exposure. Nevertheless, the fabrication and
demonstration of laser patterned MoS2 devices starting from the metallic
polymorph has not been demonstrated yet. Here, we study the effects of laser
radiation on 1T/1T'-MoS2 transistors with the prospect of driving an in-situ
phase transition to the 2H-polymorph through light exposure. We find that
although the Raman peaks of 2H-MoS2 become more prominent and the ones from the
1T/1T' phase fade after the laser exposure, the semiconducting properties of
the laser patterned devices are not fully restored and the laser treatment
ultimately leads to degradation of the transport channel
Thickness dependent interlayer transport in vertical MoS2 Josephson junctions
We report on observations of thickness dependent Josephson coupling and
multiple Andreev reflections (MAR) in vertically stacked molybdenum disulfide
(MoS2) - molybdenum rhenium (MoRe) Josephson junctions. MoRe, a chemically
inert superconductor, allows for oxide free fabrication of high transparency
vertical MoS2 devices. Single and bilayer MoS2 junctions display relatively
large critical currents (up to 2.5 uA) and the appearance of sub-gap structure
given by MAR. In three and four layer thick devices we observe orders of
magnitude lower critical currents (sub-nA) and reduced quasiparticle gaps due
to proximitized MoS2 layers in contact with MoRe. We anticipate that this
device architecture could be easily extended to other 2D materials.Comment: 18 pages, 6 figures including Supporting Informatio
On-Chip Sub-Diffraction THz Spectroscopy of Materials and Liquids
This chapter summarizes the trends in terahertz measurements on the surface of rigid and flexible substrates. It focuses on research incorporating fast photoconductive switches to generate and detect on-chip THz pulses using a femtosecond laser. The chapter aims to review progress toward the study of picosecond dynamics and THz spectroscopy of materials and liquids. We emphasize general sub-diffraction techniques for THz spectroscopy, transmission line and waveguide design considerations, time-domain measurements for studies of material dynamics, and provide a survey of recent research on the THz spectroscopy of materials and liquids on-chip. We conclude with an outlook on the field and highlight promising new directions. This chapter is meant to be an introduction and a general guide to this emerging field for new researchers interested in on-chip THz studies
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