月: 2024年2月

下記の通り九州支部第182回講演会を開催いたします。
皆様のご参加をお待ちしております。

日 時：2024年2月29日（木）14：00〜16：30
場 所：九州大学伊都キャンパス　ウエスト2号館8階821号室
講 師：Prof. Galia Pozina and Prof. Ching-Lien Hsiao
　　 　スウェーデン Linköping University

講演題目：Development of epitaxial ultra-wide-bandgap semiconductors Ga2O3（Prof. Galia Pozi）

講演概要：The development of the semiconductor gallium oxide (Ga2O3) currently attracts
significant attention in research due to its promising material properties. These include
an ultra-wide bandgap with an energy of 4.8 eV and an exceptionally high breakdown
electric field of ~8 MV/cm for the β-polymorph. Considering that Ga2O3 can outperform
GaN and SiC in terms of high-voltage electronics, this semiconductor is important for
many potential applications from efficient solar and wind energy conversion to
environmentally friendly electric vehicles. However, for Ga2O3 to be effectively utilized
in power electronics, there is a need to improve the growth techniques to produce highquality
single crystal epitaxial layers suitable for device structures. The primary
challenge in fully using Ga2O3 for high-voltage device applications lies in overcoming
difficulties associated with achieving suitable and controllable electrical conductivity,
especially of p-type. Various growth methods, including molecular beam epitaxy (MBE)
and metal-organic vapor-phase epitaxy (MOVPE), have been widely employed to
synthesize thin films of homoepitaxial and heteroepitaxial Ga2O3. Additionally, the use
of the high-growth-rate method such as halide vapor-phase epitaxy (HVPE), which we
employ, has been proven to be successful, with growth rates reaching up to tens of
μm/h. This approach is particularly effective in depositing thick layers of Ga2O3, which
can be utilized either fabricating devise or as templates for subsequent MBE or
MOVPE growth.

講演題目：Engineering of advanced III-nitride nanostructures for optic and electronic applications
        （Prof. Ching-Lien Hsiao）

講演概要：Iridescent structural colors and polarization properties of the light shown in the
reflection from insects, such as butterflies and scarab beetles, attract attention to
explore the relationship between the microstructures and their optical behaviors. These
structures, which help organisms survive in nature’s tough environments, also inspire
biomimetic-based applications. Engineering of advanced nanostructures in
morphology, structure, and composition paves a way to obtain unique characteristics
by resembling these natural structures. In this talk, I will give an overview on how to
grow nanostructures using conventional vacuum techniques. Mostly, I will address on
industrial-compatible process, magnetron sputter epitaxy. The growth mechanism will
be elucidated from nucleation to the formation of mature nanostructures through
detailed microstructural characterizations on morphology, structure, and composition.
The controlled growth of advanced multi-component/-layer nanostructures by means
of manipulating the growth configurations of deposition system will be presented.
Specific site-controlled growth of nanostructures on prepatterned substrates for
making regular nanorod arrays will be introduced. Finally, I will give some examples of
application utilizing the characteristics of these advanced nanostructures for optic and
electronic applications.

連絡先：九州大学工学研究院 エネルギー量子工学部門 安田和弘
電子メール：yasuda.kazuhiro.967@m,kyushu-u.ac.jp、電話：092-802-3487