Admittance Spectroscopy Up to 67 GHz in InGaAs/InAlAs Triple-Barrier Resonant Tunneling Diodes. - Kotaro Aikawa; Michihiko Suhara; Takumi Kimura; Junki Wakayama; Takeshi Makino; Katsuhiro Usui; Kiyoto Asakawa; Kouichi Akahane; Issei Watanabe (IEICE Trans. Electron., 2022)