Dr. Tetsuya Yamamoto, Professor and Head, Materials Design Center, Research Institute, Kochi University of Technology, Japan.

Title: Wide band gap ZnO applications

Abstract: My talk discusses current status and future prospect of wide-band-gap ZnO applications. ZnO has several advantages over nitride semiconductors such as gallium nitride (GaN) in the application range, however, the most important being its larger exciton binding energy, the ability to grow single crystal substrates and deposit highly oriented polycrystalline films at low temperatures at amorphous glass or polymer substrates. Other favorable aspects of ZnO include its broad chemistry leading to many opportunities for wet chemical etching, low power threshold for optical pumping, radiation hardness, and biocompatibility such as antibacterial substances. Together, these properties of ZnO make it an ideal candidate for a variety of devices ranging from chemical sensors through to deep and vacuum ultra-violet applications and nanotechnology-based devices such as displays. We, very recently, reported low-optical-loss transparent conductive Ga-doped ZnO films for plasmonics in the near-infrared spectral range. We achieved 200-nm-thick GZO films with the cross-over wavelength adjusted to 1.476 micron meter, exhibiting a very low imaginary part of the dielectric function of 0.434 at the telecommunication wavelength of 1.5 micron meter. Precise control of carrier concentration together with tailor-making of carrier transport enables us with successful achievement above. We will discuss the issue to be resolved, especially, the improvement of carrier transport of ZnO films by clarifying a key factor to achieve very high Hall mobility In 2 O 3 codoped with Ce and H atoms.