Chemical vapor deposition of ordered structures in YAG–alumina eutectic system

The eutectic structure of metals and ceramics is the result of a self‐organization phenomenon in which multiple solid phases solidify with an ordered structure from a liquid phase. Hence, a melt‐solidification process was the only way to generate ordered structures in a ceramic eutectic system. Here, we prepared ordered structures of Y3Al5O12 (YAG)–Al2O3 composites via chemical vapor deposition in the YAG–Al2O3 eutectic system. Spatially periodic YAG rod and lamellar structures were generated in an alumina matrix homoepitaxially grown on the sapphire substrates on the Al2O3‐rich side of the eutectic composition, whereas α‐Al2O3 rod and lamellar structures were generated in a YAG matrix on the Y2O3‐rich side. The results reveal that the pattern formation of ordered structures in a ceramic eutectic system can occur not only during in the melt‐solidification process but also during the vapor deposition process. The Ce3+‐doped YAG–Al2O3 composite film converts some of the blue light into yellow light, allowing some of it to pass through, and emitting white light. The Eu3+‐doped YAG–Al2O3 composite film can be utilized as a scintillation screen for a high‐resolution X‐ray imaging test to see though a semiconductor storage device.