Three‐Dimensional Photonic Crystals with Non‐spherical Colloids as Building Blocks

This paper discusses the potential use of non‐spherical colloids (see Figure) as the building blocks in self‐assembly to fabricate three‐dimensional photonic crystals with bandgaps located in the optical regime. The methods of producing non‐spherical colloids as monodisperse samples, and with well‐defined shapes and tightly controlled dimensions are presented, and the methods employed to organize these non‐spherical colloids into 3D crystalline lattices are discussed.     

Powder‐Based Ceramic Meso‐ and Microscale Fabrication Processes

Processing techniques are reviewed that allow the introduction of ceramic components made from powders into microelectromechanical systems (MEMS). Ceramics have several advantages over other materials also in microsystems, e.g., heat resistance, hardness, corrosion resistivity, or functional properties. The range of available materials in microfabrication technology is being increased beyond those deposited by thin‐film technology. Top–down approaches like mechanical and laser‐based direct writing processes, ink‐jet printing, microextrusion, and lithography‐based methods are presented. They are complemented by some more fundamental work in the field of bottom–up synthesis of micro‐ and nanoscaled ceramic materials.     

Inside Front Cover: Plasma‐Assisted Synthesis of Silicon Nanocrystal Inks (Adv. Mater. 18/2007)

The inside cover shows a photo and a schematic of a two‐step nonthermal plasma process used to produced silicon nanocrystal inks, that is, stable colloidal solutions of silicon nanocrystals. In the first (upper) plasma, nanocrystals are formed through plasma‐induced dissociation of silane molecules, leading to nanocrystal nucleation through chemical clustering. In the second (lower) plasma step, organic ligands are attached in‐flight to the silicon nanocrystal surfaces. The collected powder of surface functionalized silicon nanocrystals readily forms stable colloidal solutions in nonpolar solvents, report Lorenzo Mangolini and Uwe Kortshagen on p. 2513.