Searching for room temperature magnetic two-dimensional (2D) materials is a charming goal, but the number of satisfied materials is tiny. Strain can introduce considerable deformation into the lattice structure of 2D materials, and thus significantly modulate their intrinsic properties. In this work, we demonstrated a remarkable strain-modulated magnetic properties in the chemical vapor deposited Cr2Te3 nanoflakes grown on mica substrate. We found the Curie temperature of Cr2Te3 nanoflakes can be positively and negatively modulated under tensile and compressive strain respectively, with a maximum varied value of ~ 40 and −90 K, dependent on the thickness of samples. Besides, the coercive field of Cr2Te3 nanoflakes also showed a significant decrease under the applied strain, suggesting the decrease of exchange interaction or the change of the magnetization direction. This work suggests a promise to employ interfacial strain to accelerate the practical application of room temperature 2D magnetics.
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Infrared (IR) light photodetection based on two dimensional (2D) materials of proper bandgap has attracted increasing attention. However, the weak IR absorption in 2D materials, due to their ultrathin attribute and indirect bandgap in multilayer structures, degrades their performance when used as IR photodetectors. In this work, we utilize the fact that few-layer MoTe2 flake has a near-IR (NIR) bandgap and demonstrate a ~ 60-fold enhancement of NIR response by introducing a gold hollow nanorods on the surface. Such gold hollow nanorods have distinct absorption peak located also at the NIR regime, therefore induces strong resonance, benefitting NIR absorption in MoTe2, resulting in strong near-field enhancement. With the evidence from steady and transient state optical spectra, we confirm that the enhancement of NIR response originates only photon absorption, rather than electron transport at interfaces as observed in other heterostructures, therefore, precluding the requirement of high-quality interfaces for commercial applications.
Two dimensional (2D) nanomaterials are promising fundamental building blocks for use in the next-generation semiconductor industry due to their unique geometry and excellent (opto)-electronic properties. However, large scale high quality fabrication of 2D nanomaterials remains challenging. Thus, the development of controllable fabrication methods for 2D materials is essential for their future practical application. In this review, we will discuss the importance of the space-confined vapor deposition strategy in the controllable fabrication of 2D materials and summarize recent progress in the utilization of this strategy for the synthesis of novel materials or structures. Using this method, various high quality ultrathin 2D materials, including large-area graphene and boron nitride, ReS2/ReSe2, HfS2, pyramid-structured multilayer MoS2, and the topological insulators Bi2Se3 and Bi2Te3, have been successfully obtained. Additionally, by utilizing van der Waals epitaxy growth substrates such as mica or other 2D materials, patterned growth of 2D nanomaterials can be easily achieved via a surface-induced growth mechanism. Finally, we provide a short prospect for future development of this strategy.