2 research outputs found
Nonfaradaic Nanoporous Electrochemistry for Conductometry at High Electrolyte Concentration
Nanoporous electrified surfaces create
a unique nonfaradaic electrochemical
behavior that is sensitively influenced by pore size, morphology,
ionic strength, and electric field modulation. Here, we report the
contributions of ion concentration and applied ac frequency to the
electrode impedance through an electrical double layer overlap and
ion transport along the nanopores. Nanoporous Pt with uniform pore
size and geometry (L<sub>2</sub>-ePt) responded more sensitively to
conductivity changes in aqueous solutions than Pt black with poor
uniformity despite similar real surface areas and enabled the previously
difficult quantitative conductometry measurements at high electrolyte
concentrations. The nanopores of L<sub>2</sub>-ePt were more effective
in reducing the electrode impedance and exhibited superior linear
responses to not only flat Pt but also Pt black, leading to successful
conductometric detection in ion chromatography without ion suppressors
and at high ionic strengths
Nonconventional Strain Engineering for Uniform Biaxial Tensile Strain in MoS<sub>2</sub> Thin Film Transistors
Strain engineering has been employed
as a crucial technique
to
enhance the electrical properties of semiconductors, especially in
Si transistor technologies. Recent theoretical investigations have
suggested that strain engineering can also markedly enhance the carrier
mobility of two-dimensional (2D) transition-metal dichalcogenides
(TMDs). The conventional methods used in strain engineering for Si
and other bulk semiconductors are difficult to adapt to ultrathin
2D TMDs. Here, we report a strain engineering approach to apply the
biaxial
tensile strain to MoS2. Metal-organic chemical vapour deposition
(MOCVD)-grown large-area MoS2 films were transferred onto
SiO2/Si substrate, followed by the selective removal of
the underneath Si. The release of compressive residual stress in the
oxide layer induces strain in MoS2 on top of the SiO2 layer. The amount of strain can be precisely controlled by
the thickness of oxide stressors. After the transistors were fabricated
with strained MoS2 films, the array of strained transistors
was transferred onto plastic substrates. This process ensured that
the MoS2 channels maintained a consistent tensile strain
value across a large area