Understanding vapor phase growth of hexagonal boron nitride.

Hexagonal boron nitride (BN), with its atomically flat structure, excellent chemical stability, and large band gap energy (∼6 eV), serves as an exemplary 2D insulator in electronics. Additionally, it offers exceptional attributes for the growth and encapsulation of semiconductor transition metal dichalcogenides (TMDCs). Current methodologies for producing BN thin films primarily involve exfoliating multi-layer or bulk crystals and thin film growth chemical vapor deposition (CVD), which entails the thermal decomposition and surface reaction of molecular precursors like ammonia boranes (NHBH) and borazine (BNH).

Synthesis and theoretical study of a mixed-ligand indium(III) complex for fabrication of β-InS thin films chemical vapor deposition.

Two new heteroleptic indium aminothiolate compounds [InClSCHN(Me)SCH][1] and [InSCHN(Me)SCH(CHFNO)] [2] were synthesized by salt metathesis reaction involving indium trichloride, aminothiol, and N,O-β-heteroarylalkenol ligands. The complexes were subsequently purified and thoroughly characterized by nuclear magnetic resonance (NMR) analysis, elemental studies, mass spectroscopy, and X-ray diffraction single crystal analysis that showed a trigonal bipyramidal coordination of In(III) in both complexes. Thermogravimetric analysis of [1] revealed a multistep decomposition pathway and the formation of InS at 350 °C, which differed from the pattern of [2] due to the lower thermal stability of [1].

Direct Synthesis of Two-Dimensional SnSe and SnSe through Molecular Scale Preorganization.

Two-dimensional tin monoselenide (SnSe) and tin diselenide (SnSe) materials were efficiently produced by the thermolysis of molecular compounds based on a new class of seleno-ligands. Main group metal chalcogenides are of fundamental interest due to their layered structures, thickness-dependent modulation in electronic structure, and small effective mass, which make them attractive candidates for optoelectronic applications. We demonstrate here the synthesis of stable tin selenide precursors by reductive bond cleavage in the dimeric diselenide ligand (SeCHN(Me)CHSe) in the presence of SnCl.

Single source precursor route to nanometric tin chalcogenides.

Low-temperature solution phase synthesis of nanomaterials using designed molecular precursors enjoys tremendous advantages over traditional high-temperature solid-state synthesis. These include atomic-level control over stoichiometry, homogeneous elemental dispersion and uniformly distributed nanoparticles. For exploiting these advantages, however, rationally designed molecular complexes having certain properties are usually required.

Influence of the choice of precursors on the synthesis of two-dimensional transition metal dichalcogenides.

The interest in transition metal dichalcogenides (TMDCs; ME; M = transition metal; E = chalcogenide, y = valence of the metal) has grown exponentially across various science and engineering disciplines due to their unique structural chemistry manifested in a two-dimensional lattice that results in extraordinary electronic and transport properties desired for applications in sensors, energy storage and optoelectronic devices. Since the properties of TMDCs can be tailored by changing the stacking sequence of 2D monolayers with similar or dis-similar materials, a number of synthetic routes essentially based on the disintegration of bulk (, chemical exfoliation) or the integration of atomic constituents (, vapor phase growth) have been explored. Despite a large body of data available on the chemical synthesis of TMDCs, experimental strategies with high repeatability of control over film thickness, phase and compositional purity remain elusive, which calls for innovative synthetic concepts offering, for instance, self-limited growth in the -direction and homogeneous lateral topography.

Accounting for multiple ecosystem services in a simulation of land-use decisions: Does it reduce tropical deforestation?

Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio-economic objectives in decision-making. To test the effect of accounting for both ES and socio-economic objectives in land-use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests.

Compositional diversity of rehabilitated tropical lands supports multiple ecosystem services and buffers uncertainties.

High landscape diversity is assumed to increase the number and level of ecosystem services. However, the interactions between ecosystem service provision, disturbance and landscape composition are poorly understood. Here we present a novel approach to include uncertainty in the optimization of land allocation for improving the provision of multiple ecosystem services.

Survival of Norway spruce remains higher in mixed stands under a dryer and warmer climate.

Shifts in tree species distributions caused by climatic change are expected to cause severe losses in the economic value of European forestland. However, this projection disregards potential adaptation options such as tree species conversion, shorter production periods, or establishment of mixed species forests. The effect of tree species mixture has, as yet, not been quantitatively investigated for its potential to mitigate future increases in production risks.