Transmission properties of van der Waals materials for terahertz time-domain spectroscopy applications

Abstract

This work contains results from studying the electro-optical properties of bulk and few-layered Van der Waals materials including intercalated graphene, phosphorene, and tungsten disulfide thin films. Different production methods and substrates are considered. The objective of the research is to assess the relevance of application of these materials in terahertz (THz) time-domain spectroscopy (TDS). Therefore, the study is conducted in the visible, NIR (near-infrared) and THz frequency ranges as the most critically in need of research when searching for effective materials for TDS.

Anisotropy of Optical Properties of Hexagonal Boron Nitride Films

“…To obtain homogeneous thin films of multilayered h-BN layers laid on each other, the redispersed solution was filtered through a microporous (with a pore size of 0.2 μm) polytetrafluoroethylene membrane. Such films were widely studied for different two-dimensional materials and it was shown that dispersions of graphene oxides and molybdenum disulfide yielded high-quality films [3][4][5][6][7]. The thin films obtained as a result of dispersion filtration were transported or deposited by the method described above [8][9][10].…”

Anisotropic Optical Properties of Hexagonal Boron Nitride Thin Films

“…High quality films have been successfully developed using other two-dimensional materials (for example from dispersions of graphene oxide and molybdenum disulfide [4][5][6]), but not previously for h-BN. The thin films produced from filtering of the dispersion was achieved in accordance with a previously described method [7,8], marking a facile and scaleable method towards large-scale integration of the two-dimensional material. The membrane holding the thin film was carefully transferred to the desired (PET) substrate, with the side with the filtered h-BN in contact with the substrate surface.…”

Boron Nitride Thin Films with Anisotropic Optical Properties from Microscale Particle Density Distributions

“…High quality films have been successfully developed using other two-dimensional materials (for example from dispersions of graphene oxide and molybdenum disulfide [23,39,40]), but not previously for h-BN. The thin films produced from filtering of the dispersion was achieved in accordance with a previously described method [22,25], marking a facile and scaleable method towards large-scale integration of the two-dimensional material. The membrane holding the thin film was carefully transferred to the desired (PET) substrate, with the side with the filtered h-BN in contact with the substrate surface.…”

“…Additionally, the average size of the exfoliated particles is significantly less than the original bulk crystal(s) [21,23]. Hence, to produce large area devices using ultrasonicated 2D materials, it is necessary to fabricate thin films of the individual exfoliated particles of similar size and shape, that are uniformly distributed [23][24][25][26].…”