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Heterostructures may exhibit completely new physical properties that may be otherwise absent in their individual component materials. However, how to precisely grow or assemble desired complex heterostructures is still a significant challenge. In this work, the collision dynamics of a carbon nanotube and a boron nitride nanotube under different collision modes were investigated using the self-consistent-charge density-functional tight-binding molecular dynamics method. The energetic stability and electronic structures of the heterostructure after collision were calculated using the first-principles calculations. Five main collision outcomes are observed, that is, two nanotubes can (1) bounce back, (2) connect, (3) fuse into a defect-free BCN heteronanotube with a larger diameter, (4) form a heteronanoribbon of graphene and hexagonal boron nitride and (5) create serious damage after collision. It was found that both the BCN single-wall nanotube and the heteronanoribbon created by collision are the direct band-gap semiconductors with the band gaps of 0.808 eV and 0.544 eV, respectively. These results indicate that collision fusion is a viable method to create various complex heterostructures with new physical properties. [ABSTRACT FROM AUTHOR]

2D Janus transition metal dichalcogenide (TMD) semiconductor materials have attracted great interest for their potential applications. Because of the increased requirement for thermal management in 2D devices with single‐atom thickness, a fundamental understanding of interfacial thermal conduction (ITC) has emerging significance. In this work, the ITC of in‐plane heterostructures constructed using MoSSe and WSSe is reported. In addition to the interface connected normally by MoSSe and WSSe with the same type of chalcogen atoms are on the same side of left and right sections, inversional interface by rotation of 180° of WSSe is also considered, in which S atoms are on the opposite side of the left and right sections. Interestingly, the ITC in the normally connected heterostructure is found to be almost twice as much as that in the inversely connected heterostructure. The unusually large change in ITC is attributed to the bending curvature and additional discontinuity in the inversely connected heterostructure. Euler–Bernoulli beam model gives further insight into the origin of such interface bending. The findings offer the very first insight into the phonon transport in Janus heterostructures, and benefit thermal management of 2D devices based on Janus monolayers. [ABSTRACT FROM AUTHOR]

This work investigates interfacial thermal transport in phononic‐mismatched heterostructures that consists of pristine black phosphorene and its phononic crystal. It is found that the presence of the sub‐periodic structure results in reduced thermal conductivity in phononic crystals. As opposed to intuitive expectations, a slight temperature jump is observed at the interface of nanophononic heterostructures, which is only about 10% of that at conventional interfaces consisting of dissimilar materials. Consequently, contact thermal conductance in the nanophononic heterostructure is 10−30 times higher than that of mass‐mismatched interfaces in a comparative study. Moreover, in contrast to conventional heterostructures achieved by interfacing dissimilar materials, weak temperature dependence is observed in interfacial thermal conductance, and thermal rectification is sharply suppressed. These phenomena are well explained based on lattice dynamic insights. This work not only enhances the understanding of the fundamental physics of phonons transport across interface, but also facilitates the possible spectrum of application ranges from thermoelectrics, thermal management, to thermal cloak. [ABSTRACT FROM AUTHOR]

Based on first-principles calculations, we systematically investigate the electronic and optical properties of van der Waals (vdW) heterostructures composed of graphene-like gallium nitride (g-GaN) and transition metal dichalcogenides (TMDs). The investigated vdW heterostructures (g-GaN/MoS 2 , g-GaN/WS 2 , g-GaN/MoSe 2 , and g-GaN/WSe 2) are all semiconductors with direct bandgap. In particular, both the g-GaN/MoS 2 and g-GaN/WS 2 vdW heterostructures possess type-II band alignment, which will facilitate the separation of photogenerated carriers, and enhance their lifetime. Furthermore, band edge positions of these two heterostructures satisfied both water oxidation and reduction energy requirements, suggesting the potential in photocatalysts for water splitting. In addition, both g-GaN/MoS 2 and g-GaN/WS 2 vdW heterostructures exhibit a high electron mobility, which ensure that the redox reactions for water splitting will be effectively proceeded. More importantly, they show significant absorption peaks in the visible light region, leading to highly efficient utilization of the solar energy. These fascinating properties render the g-GaN/MoS 2 and g-GaN/WS 2 vdW heterostructures high-efficiency photocatalysts for water splitting. Unlabelled Image • Many g-GaN/TMD vdW heterostructures are direct-bandgap semiconductors. • Both g-GaN/MoS 2 and g-GaN/WS 2 form type-II heterostructure. • g-GaN/MoS 2 and g-GaN/WS 2 satisfy both water oxidation and reduction potential levels. • Both g-GaN/MoSe 2 and g-GaN/WSe 2 vdW heterostructures have type-I band alignment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The most stable structures of the vertical heterostructures of MX 2 /BP (M =Mo, W; X =S, Se) are obtained. • Van der Waals interaction are found in these heterostructures. • Type-II band alignment are addressed in MoSe 2 /BP and WSe 2 /BP which can separate the photogenerated-charge. • All these heterostructures have excellent ability of optical absorption in the near-infrared and visible regions. Abstract Van der Waals (vdW) heterostructure can improve the performance of the 2D materials and provide more applications. Based on density functional theory (DFT) calculations, the properties of vertical heterostructures formed by transition metal dichalcogenides (TMDs) MX 2 (M = Mo, W; X = S, Se) and boron nitride (BP) were addressed. In particular, the vdW interaction exist in all these heterostructures instead of covalent bonding. The MoSe 2 /BP and WSe 2 /BP vdW heterostructures possess direct bandgap characterized by type-II band alignment and powerful built-in electric field across the interface, which can effectively separate the photogenerated-charge. Meanwhile, the MoS 2 /BP and WS 2 /BP vdW heterostructures also have the direct bandgap and intrinsic type-I band alignment. Furthermore, all heterostructures exhibit excellent optical absorption in the visible and near-infrared regions. Our investigation shows an effective method to design new vdW heterostructures based on TMDs and explores their applications for photocatalytic, photovoltaic, and optical devices. [ABSTRACT FROM AUTHOR]

Abstract Four vertical heterostructures based on two-dimensional transition-metal dichalcogenides (TMDs) – MoS 2 /GeC, MoSe 2 /GeC, WS 2 /GeC, and WSe 2 /GeC, were studied by density functional theory calculations to investigate their structure, electronic characteristics, principle of photogenerated electron–hole separation, and optical-absorption capability. The optimized heterostructures were formed by van der Waals (vdW) forces and without covalent bonding. Their most stable geometric configurations and band structures display type-II band alignment, which allows them to spontaneously separate photogenerated electrons and holes. The charge difference and built-in electric field across the interface of these vdW heterostructures also contribute to preventing the photogenerated electron–hole recombination. Finally, the high optical absorption of the four TMD-based vdW heterostructures in the visible and near-infrared regions indicates their suitability for photocatalytic, photovoltaic, and optical devices. Highlights • The most stable structures of the vertical heterostructures of TMDs/GeC are obtained. • Van der Waals interaction are found in these heterostructures. • Type-II band alignment are addressed in all the vdW heterostructures which can separate the photogenerated-charge. • All the structures are suitable for photocatalytic, photovoltaic, and optical devices. • All the structures show high optical absorption in the visible and NIR ranges. [ABSTRACT FROM AUTHOR]

After the discovery of graphene, a lot of research has been conducted on two-dimensional (2D) materials. In order to increase the performance of 2D materials and expand their applications, two different layered materials are usually combined by van der Waals (vdW) interactions to form a heterostructure. In this work, based on first-principles calculation, some charming properties of the heterostructure constructed by Hf2CO2, AlN and GaN are addressed. The results show that Hf2CO2/AlN and Hf2CO2/GaN vdW heterostructures can keep their original band structure shape and have strong thermal stability at 300 K. In addition, the Hf2CO2/MN heterostructure has I-type band alignment structure, which can be used as a promising light-emitting device material. The charge transfer between the Hf2CO2 and AlN (or GaN) monolayers is 0.1513 (or 0.0414) |e|. The potential of Hf2CO2/AlN and Hf2CO2/GaN vdW heterostructures decreases by 6.445 eV and 3.752 eV, respectively, across the interface. Furthermore, both Hf2CO2/AlN and Hf2CO2/GaN heterostructures have remarkable optical absorption capacity, which further shows the application prospect of the Hf2CO2/MN heterostructure. The study of this work provides theoretical guidance for the design of heterostructures for use as photocatalytic and photovoltaic devices. [ABSTRACT FROM AUTHOR]