Vortrag: Gallium oxide from materials to device
Einladung zum Physikalischen Kolloquium "Gallium oxide from materials to devices"
Dr. Klaus Irmscher
Leibniz-Institut für Kristallzüchtung Berlin
Monoclinic gallium oxide (β-Ga2O3) belongs to the transparent semiconducting oxides. It is distinguished by its ultra-wide bandgap of about 4.8 eV, which is the reason for an optical transparency range extending deep into the ultraviolet and for a high break-down electric field estimated at 8 MV/cm. Combined with the feasibility of n-type doping by Si, Sn, or Ge, β-Ga2O3 has great potential as a material for deep ultraviolet photodetection and for high-power electronics. In particular in the latter field, there is presently a flood of publications and it might be really possible that gallium oxide outperforms GaN and SiC as power electronics material.
In the talk, the crystal structure and the electronic band structure of β-Ga2O3 are shortly introduced. Consequences for the optical and electrical properties are derived. The main part deals with doping and defects issues in β-Ga2O3 by comparing theoretical predictions with experimental findings. Compensation and mobility reduction due to the presence of extended defects are demonstrated for twin lamellae in n-type doped layers grown by metal organic vapor phase epitaxy. Measures for twin-free growth are described. Finally, compensation by point defects, in particular by transition metals and gallium vacancies in combination with hydrogen, is discussed.
Alle Interessenten sind zu diesem Vortrag herzlich eingeladen.