In this paper, we report on a new system of three-dimensional (3D) printing for a magnetic elastomer that contains magnetic particles. Not only can we fabricate a three-dimensional structure, but we can also control the magnetically anisotropic property of each position in the structure using the present technique. Our new system employed photocurable poly(dimethylsiloxane) (PDMS) as the base material so that a method similar to a conventional 3D printing process with photolithography can be used. A magnetic powder was mixed with photocurable PDMS, and particle chain clusters were obtained by applying a magnetic field during the curing process. These chain clusters provide an anisotropic property in each part of the printed structure. We show some results of preliminary experiments and 3D printed samples in this paper. If the fabricated structure was placed under an applied magnetic field, each chain cluster will cause the rotational moment to be along the magnetic flux line, which can deform a soft matrix body. This deformation can be used as a magnetic actuator for the structure. Variable deformable structures could be developed using the present method.

High‐brightness micro‐LED display bonded onto silicon backplane has been successfully demonstrated. The 0.38‐inch full‐colour active matrix LED microdisplay system consists of 352 × 198 pixels. Each pixel is 24 μm square composed of red, green, and blue (RGB) subpixels corresponding to a pixel resolution of 1053 ppi. Quantum‐dot materials are formed on III‐nitride blue micro‐LED array to convert blue light into red and green for full‐colour operation. We have confirmed that this microdisplay, which we call “Silicon Display” has wide colour gamut exceeding 120% of sRGB. We describe the advantage of this colour‐converting approach for the full‐colour micro‐LEDs. Progress toward higher resolution is also described. Brightness of more than 30 000 cd/m2 has been confirmed at a driving current density of 4 A/cm2 for 3000 ppi blue monochrome micro‐LED prepared for full‐colour Silicon Display. We believe our “Silicon Display” is ideally suited for near‐to‐eye displays for augmented and mixed reality.

The reaction of oxygen with H2S-treated GaAs (001) surfaces was studied using Auger electron spectroscopy and reflection high-energy electron diffraction. GaAs surfaces in situ treated with H2S gas were exposed to pure oxygen gas with and without simultaneous light illumination of a halogen lamp. It was shown that the oxygen uptake on a H2S-treated surface is much less than that on an untreated bare GaAs surface. Surfaces exposed to oxygen were heated in an ultrahigh-vacuum environment in order to study the desorption of the reacted oxygen. The oxygen Auger signal was found to easily disappear when the surface was heated to 520 °C, leaving sulfur atoms on the surface. The oxide formed on a bare GaAs surface with light illumination was found to be relatively thick; it did not desorb completely until it was heated to about 550 °C. These results indicate that oxide on a H2S-treated surface is formed only on the top surface.

Highly reliable operation of 405 nm laser diodes for high-density optical storage was demonstrated. Introduction of epitaxially grown AlON layer between the front facet and normal coating layer was shown to be effective to suppress catastrophic optical damage at the laser facet. Stable operation in excess of 1000 h was confirmed at an output power of 500 mW in a pulsed-mode at a case temperature of 80 °C.

Molecular-beam epitaxy of an (Al)GaAsN alloy was demonstrated using uncracked ammonia as the nitrogen source. It was found that the efficiency of nitrogen incorporation into the alloy layers was dramatically enhanced when aluminum flux was supplied during growth. The nitrogen composition of an Al0.07Ga0.93As1−yNy layer grown at 580 °C was approximately 100 times larger than that of a GaAs1−yNy layer grown at the same growth condition without the aluminum supply. The nitrogen incorporation into the AlxGa1−xAs1−yNy layers was found to be proportional to the aluminum composition x. The activation energy of nitrogen incorporation was measured to be 195 kJ/mol.