Realization of 2D crystalline metal nitrides via selective atomic substitution

Abstract

Two-dimensional (2D) transition metal nitrides (TMNs) are new members in the 2D materials family with a wide range of applications. Particularly, highly crystalline and large area thin films of TMNs are potentially promising for applications in electronic and optoelectronic devices; however, the synthesis of such TMNs has not yet been achieved. Here, we report the synthesis of few-nanometer thin Mo5N6 crystals with large area and high quality via in situ chemical conversion of layered MoS2 crystals. The structure and quality of the ultrathin Mo5N6 crystal are confirmed using transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The large lateral dimensions of Mo5N6 crystals are inherited from the MoS2 crystals that are used for the conversion. Atomic force microscopy characterization reveals the thickness of Mo5N6 crystals is reduced to about 1/3 of the MoS2 crystal. Electrical measurements show the obtained Mo5N6 samples are metallic with high electrical conductivity (~ 100 Ω sq -1 ), which is comparable to graphene. The versatility of this general approach is demonstrated by expanding the method to synthesize W5N6 and TiN. Our strategy offers a new direction for preparing 2D TMNs with desirable characteristics, opening a door for studying fundamental physics and facilitating the development of next generation electronics.

Electrocatalytic Hydrogen Evolution of Ultrathin Co‐Mo5N6 Heterojunction with Interfacial Electron Redistribution

“…After nitridation treatment, as confirmed by the XRD pattern ( Figure 1 a), all the diffraction peaks were in good accordance with the standard PDF cards of Mo 5 N 6 (51‐1326) and Co (15‐806). Raman spectroscopy (as shown in Figure S2, Supporting Information) exhibits a peak at 215 cm −1 assigned to Mo 5 N 6 , [ 13 ] indicating the coexistence of two phases without any impurities. The as‐synthesized Co‐Mo 5 N 6 inherited the uniform morphology (Figure 1b).…”

Structure, Preparation, and Applications of 2D Material‐Based Metal–Semiconductor Heterostructures

“…[114][115] High-quality MXenes with no surface groups can be obtained by annealing a TMDC in CH4 or NH3, providing a new method for constructing 2D MSHSs. [32,[116][117] For example, Choi et al patterned a CVD-grown MoS2 film with a mask and in subsequent CH4 treatment the exposed area was converted to metallic Mo2C, while the protected MoS2 area remained unchanged ( Figure 3e). [116] The size of lateral MSHS array formed reached hundreds of micrometers.…”

“…In a similar way, under NH3 treatment, MoS2 was converted to metallic Mo5N6, and Mo5N6-MoS2 lateral MSHSs were made by controlling the reaction time. [117] Compared with growth methods like CVD, post treatment such as mentioned above does not need rigorous growth conditions. This topic should be the basis of research that greatly increase the number of existing heterostructure preparation processes.…”

Low temperature synthesis of plasmonic molybdenum nitride nanosheets for surface enhanced Raman scattering

“…Because of their excellent catalytic activity, high mechanical strength, and excellent conductivity 1 – 4 , transition metal nitrides have attracted more and more attention in catalysis 5 – 7 , energy 8 , 9 , sensing 10 – 12 , and other applications 13 – 15 . Because of their importance, researchers have synthesized a variety of transition metal nitride nanostructures, such as mesoporous VN 16 , Ti 2 N nanosheets 17 , CoN nanowires 18 , NiMoN x nanowires 19 , and Ni 3 N nanosheets 20 .…”