We theoretically and experimentally demonstrate a strong and tunable optical anisotropy in epitaxially-grown VO thin films. Using a combination of temperature-dependent X-ray diffraction, spectroscopic ellipsometry measurements and first-principle calculations, we reveal that these VO thin films present an ultra-large birefringence (Δ > 0.9).
View Article and Find Full Text PDFStacking layered two-dimensional materials in a type-II band alignment block has provided a high-performance method in photocatalytic water-splitting technology. The key parameters in such heterostructure configurations are the valence and conduction band offsets at the interface, which determine the device performance. Here, based on density functional theory calculations, the bandgap and band offsets at CN/MSe (M = Mo, W) interfaces have been engineered.
View Article and Find Full Text PDFThe rise of van der Waals hetero-structures based on transition metal dichalcogenides (TMDs) opens the door to a new generation of optoelectronic devices. A key factor controlling the operation and performance of such devices is the relative alignment of the band edges of the components. The electronic properties of the layers can be further modulated by chemical doping, typically leading to the introduction of gap states.
View Article and Find Full Text PDFStacked two-dimensional (2D) heterostructures are evolving as the "next-generation" optoelectronic materials because of the possibility of designing atomically thin devices with outstanding characteristics. However, most of the existing 2D heterostructures are governed by weak van der Waals interlayer interactions that, as often is the case, exert limited impact on the resulting properties of heterostructures relative to their constituting components. In this work, we investigate the optoelectronic properties of a novel class of 2D MP (M = Ge and Sn) materials featuring strong interlayer interactions, applying a robust theoretical framework combining density functional theory and many-body perturbation theory.
View Article and Find Full Text PDFBlack phosphorus (BP) is recently becoming more and more popular among semiconducting 2D materials for (opto)electronic applications. The controlled physisorption of molecules on the BP surface is a viable approach to modulate its optical and electronic properties. Solvents consisting of small molecules are often used for washing 2D materials or as liquid media for their chemical functionalization with larger molecules, disregarding their ability to change the opto-electronic properties of BP.
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