MXenes
have garnered significant attention due to their
atomically
thin two-dimensional structure with metallic electronic properties.
However, it has not yet been fully achieved to discover semiconducting
MXenes to implement them into gate-tunable electronics such as field-effect
transistors and phototransistors. Here, a semiconducting Ti4N3T
x
MXene synthesized by
using a modified oxygen-assisted molten salt etching method under
ambient conditions, is reported. The oxygen-rich synthesis environment
significantly enhances the etching reaction rate and selectivity of
Al from a Ti4AlN3 MAX phase, resulting in well-delaminated
and highly crystalline Ti4N3T
x
MXene with minimal defects and high content of F and O, which
led to its improved hydrophobicity and thermal stability. Notably,
the synthesized Ti4N3T
x
MXene exhibited p-type semiconducting characteristics, including
gate-tunable electrical conductivity, with a current on–off
ratio of 5 × 103 and a hole mobility of ∼0.008
cm2 V–1 s–1 at 243
K. The semiconducting property crucial for thin-film transistor applications
is evidently associated with the surface terminations and the partial
substitution of oxygen in the nitrogen lattice, as corroborated by
density functional theory (DFT) calculations. Furthermore, the synthesized
Ti4N3T
x
exhibits
strong light absorption characteristics and photocurrent generation.
These findings highlight the delaminated Ti4N3T
x
as an emerging two-dimensional semiconducting
material for potential electronic and optoelectronic applications.