Recently, hole-doped GeSe materials have been predicted to exhibit extraordinary thermoelectric performance owing largely to extremely low thermal conductivity. However, experimental research on the thermoelectric properties of GeSe has received less attention. Here, we have synthesized polycrystalline Na-doped GeSe compounds, characterized their crystal structure, and measured their thermoelec...

Improving the thermoelectric efficiency is one of the greatest challenges in materials science. The recent discovery of excellent thermoelectric performance in simple orthorhombic SnSe crystal offers new promise in this prospect [Zhao et al. Nature 508, 373 (2014)]. By calculating the thermoelectric properties of orthorhombic IV-VI compounds GeS,GeSe,SnS, and SnSe based on the first-principles ...

New designs for electro-optical free-space and waveguided 2 x 2 switches are presented and analyzed at the 1.55 μm telecoms wavelength. The proposed devices employ a ~10 nm film of GeSe that is electrically actuated to transition the layer forth-and-back from the amorphous to the crystal phase, yielding a switch with two self-sustaining states. This phase change material was selected for its ve...

Germanium selenide (GeSe) is a unique two-dimensional (2D) material showing various polymorphs stable at ambient conditions. Recently, new phase with layered hexagonal lattice (γ-GeSe) was synthesized stability and extraordinary electronic conductivity, even higher than that of graphite, while its monolayer semiconducting. In this work, using first-principles derived force constants the Boltzma...

The combined gradient echo/spin echo (GESE) sequence has been used to measure T2 and T2* simultaneously in the brain at 7T in both healthy volunteers and patients . GESE is particularly useful at 7T as it is insensitive to RF pulse errors since errors in either of the pulse flip angles will cause constant attenuation of all the echoes, leading to a simple reduction in SNR, and it has a low SAR....

Recent discovery of a novel hexagonal phase GeSe (Gamma-GeSe) has triggered great interests in nanoelectronics applications owing to its electrical conductivity bulk even higher than graphite while monolayer is semiconductor. For potential applications, construction functional two-dimensional (2D) contacts indispensable. Herein, via first-principles calculations, we propose the design van der W...

The atomic-scale structure of germanium diselenide (GeSe(2)) glass has been revisited using a combination of high-energy x-ray diffraction and constrained reverse Monte Carlo simulations. The study shows that the glass structure may be very well described in terms of a continuous network of corner- and edge-sharing Ge-Se(4) tetrahedra. The result is in contrast to other recent studies asserting...

Nanowires of GeS(2) and GeSe(2) have been obtained by novel chemical routes involving the decomposition of organo-ammonium precursors containing super-tetrahedral Ge(4)S(10) and the dimeric Ge(2)Se(6) units.

Mobile ions in amorphous materials have been a serious object of investigation [1], and their dynamics in disordered hosts constitute one of the major unsolved problems in the field of solid state ionics. Certain compositions of silver doped GeSe glasses (close to compositions reported here) have practical potential for novel computer memory devices [2]. The structure of the Ge– Se– Ag glasses ...

The family of group IV-VI monochalcogenides has an atomically puckered layered structure, and their atomic bond configuration suggests the possibility for realization various polymorphs. Here, we report synthesis first hexagonal polymorph from monochalcogenides, which is conventionally orthorhombic. Recently predicted four-atomic-thick GeSe, so-called {\gamma}-GeSe, synthesized clearly identifi...