The enhanced superconductivity in few layer 2H-TaS₂ and suppressed CDW transition of nanoribbon 1T-TaS₂ have been investigated in this thesis.

Transport properties of different thickness 2H-TaS₂ reveal the suppression of CDW transition signature in 2D region. Further, the electron dominant carrier density in the order of 10²² ? ∙ ??⁻³ manifests its metallic behavior. Superconductivity in atomically thin 2H-TaS₂ is strongly enhanced, the critical temperature of a trilayer sample can be up to 2.6 K compared with 0.8 K in bulk crystals. Four-probe differential resistance method measured superconducting gap fits well with BCS model. The enhanced superconductivity may be a consequence of suppression of CDW transition and the enhancement of DOS at Fermi level.

Moreover, the transport...[ Read more ]

The enhanced superconductivity in few layer 2H-TaS₂ and suppressed CDW transition of nanoribbon 1T-TaS₂ have been investigated in this thesis.

Transport properties of different thickness 2H-TaS₂ reveal the suppression of CDW transition signature in 2D region. Further, the electron dominant carrier density in the order of 10²² ? ∙ ??⁻³ manifests its metallic behavior. Superconductivity in atomically thin 2H-TaS₂ is strongly enhanced, the critical temperature of a trilayer sample can be up to 2.6 K compared with 0.8 K in bulk crystals. Four-probe differential resistance method measured superconducting gap fits well with BCS model. The enhanced superconductivity may be a consequence of suppression of CDW transition and the enhancement of DOS at Fermi level.

Moreover, the transport characterization of bulk crystal 1T- TaS₂ demonstrates its unique three CDW evolutions with temperature. After eliminating the disturbances from measurements, the RIE etched decreased width nanoribbon like channels behave similar to the decreased thickness samples, showing a suppressed CDW transition signature. And when the width of channel still goes down, the CDW transition order will be concealed. To explain this trend, we proposed a free energy theory indicating that the decreased width will introduce higher and more stable barrier between CDW transitions. Our results establish that the decreased x or y-axis of 1T- TaS₂ will also strongly affect the CDW order.