The isolation of graphene in 2004 from graphite was a defining moment for the “birth” of a field: two-dimensional (2D) materials In recent years, there has been a rapidly increasing number of papers focusing on non-graphene layered materials, including transition-metal dichalcogenides (TMDs), because of the new properties and applications that emerge upon 2D confinement Here, we review significant recent advances and important new developments in 2D materials “beyond graphene” We provide insight into the theoretical modeling and understanding of the van der Waals (vdW) forces that hold together the 2D layers in bulk solids, as well as their excitonic properties and growth morphologies Additionally, we highlight recent breakthroughs in TMD synthesis and characterization and discuss the newest families of 2D materials, including monoelement 2D materials (ie, silicene, phosphorene, etc) and transition metal carbide- and carbon nitride-based MXenes We then discuss the doping and functionalization of 2

Recent Advances in Two-Dimensional Materials beyond Graphene

Solid-state electronics

Since its discovery1, early in 1928, the scattering of light with altered frequency has been investigated in many crystals, and much valuable information has been accumulated. The significance of the results and their relation to theories of solid state are clearly matters of great interest.

/pdf/scattering-of-light-in-crystals-2vvuyvgdkj.pdf

Scattering of light in crystals

The "textbook" phonon mean free path of heat carrying phonons in silicon at room temperature is ∼40  nm. However, a large contribution to the thermal conductivity comes from low-frequency phonons with much longer mean free paths. We present a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances. Absorption of crossed laser pulses in a freestanding silicon membrane sets up a sinusoidal temperature profile that is monitored via diffraction of a probe laser beam. By changing the period of the thermal grating we vary the heat transport distance within the range ∼1-10  μm. At small distances, we observe a reduction in the effective thermal conductivity indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.

Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane

https://pure.mpg.de/pubman/item/item_3314332_3/component/file_3324953/1-s2.0-S0370157320300363-main.pdf

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

Dynamic analysis of rapid-melting growth using SiGe on insulator

http://ieeexplore.ieee.org/iel7/6867647/6874620/06874679.pdf

Impact of Sn incorporation on low temperature growth of polycrystalline-Si 1−x Ge x layers on insulators

Development of a low-temperature (≤250°C) formation technique of orientation-controlled large-grain (<;10 μm) SiGe on insulator is essential to realize flexible electronics, where various advanced devices are integrated on flexible plastic substrates (softening temperature: ~300°C). This is because SiGe provides higher carrier mobility and superior optical properties compared with Si, as well as epitaxial template of various functional materials. In line with this, we have been developing metal-induced crystallization of SiGe. This achieves selectively (100)- or (111)-oriented large-grain (≥20 μm) SiGe at low temperatures (~250°C) [1-4]. Present paper reviews our recent progress in this novel growth technique.

Ultralow-temperature catalyst-induced-crystallization of SiGe on plastic for flexible electronics

The incorporation of Sn into Ge and Si
 1-x
Ge
 x
 effectively improves on the crystalline and electronic properties. Also, Sn-related group-IV materials give us new features of energy band engineering. The development of crystal growth of Sn-related alloys is essential for extending applications of future Si nanoelectronics.

Crystal growth of Sn-related group-IV alloy thin films for advanced Si nanoelectronics

We evaluated the optical properties and the band structure of strained single crystalline Si1-x
 Sn
 x
 using spectroscopic ellipsometry. The results suggest a reduction of the band gap at the Γ point and the formation of an optical transition by Van-Hove singularity with higher Sn fraction. In addition, since the reduction of the band gap with increasing Sn fraction at the Γ point is larger than at other points, it is expected the indirect transition type Si1-x
 Sn
 x
 used in this study may eventually change to the direct transition type. Although higher Sn fraction are required to achieve direct transition type Si1-x
 Sn
 x
 , the band structure of strained single crystal Si1-x
 Sn
 x
 was experimentally clarified.

Masashi Kurosawa

Papers

Dynamic analysis of rapid-melting growth using SiGe on insulator

Impact of Sn incorporation on low temperature growth of polycrystalline-Si 1−x Ge x layers on insulators

Ultralow-temperature catalyst-induced-crystallization of SiGe on plastic for flexible electronics

Crystal growth of Sn-related group-IV alloy thin films for advanced Si nanoelectronics

Investigation of Band Structure in Strained Single Crystalline Si1-X Sn X