Blue to yellow emission from (Ga,In)/GaN quantum wells grown on pixelated silicon substrate.

It is shown that substrate pixelisation before epitaxial growth can significantly impact the emission color of semiconductor heterostructures. The wavelength emission from InGaN/GaN quantum wells can be shifted from blue to yellow simply by reducing the mesa size from 90 × 90 µm to 10 × 10 µm of the patterned silicon used as the substrate. This color shift is mainly attributed to an increase of the quantum well thickness when the mesa size decreases.

Chondrules as direct thermochemical sensors of solar protoplanetary disk gas.

Chondrules, millimeter-sized igneous spherules comprising the major component of most chondritic meteorites, formed during the first 4 million to 5 million years of the evolution of the solar protoplanetary disk and, therefore, can potentially offer important constraints on the conditions in the disk, provided that the processes that led to their formation can be understood. High-resolution cathodoluminescence (CL) survey of chondrules from various chondrite groups revealed changes of CL activator concentrations of magnesium-rich olivines. We show that these overlooked internal zoning structures provide evidence for high-temperature gas-assisted near-equilibrium epitaxial growth of olivines during chondrule formation.

Investigation of structural and electronic properties of epitaxial graphene on 3C-SiC(100)/Si(100) substrates.

Graphene has been intensively studied in recent years in order to take advantage of its unique properties. Its synthesis on SiC substrates by solid-state graphitization appears a suitable option for graphene-based electronics. However, before developing devices based on epitaxial graphene, it is desirable to understand and finely control the synthesis of material with the most promising properties.

Rotated domain network in graphene on cubic-SiC(001).

The atomic structure of the cubic-SiC(001) surface during ultra-high vacuum graphene synthesis has been studied using scanning tunneling microscopy (STM) and low-energy electron diffraction. Atomically resolved STM studies prove the synthesis of a uniform, millimeter-scale graphene overlayer consisting of nanodomains rotated by ±13.5° relative to the left angle bracket 110 right angle bracket-directed boundaries.