Film Thermoelectric Generator of Multiple 2-D Electron Gas

• Published in: IEEE transactions on electron devices Vol. 71; no. 8; pp. 4834 - 4840
• Main Authors: Uematsu, Yuto, Ishibe, Takafumi, Kozuki, Seiya, Mano, Takaaki, Ohtake, Akihiro, Miyazaki, Hideki T., Kasaya, Takeshi, Yamashita, Yuichiro, Uenuma, Mutsunori, Nakamura, Yoshiaki
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 2-D electron gas (2DEG); Conductivity; Electrical resistance; Electrical resistivity; Electrodes; Electron gas; Energy harvesting; Gallium arsenide; HEMTs; Legged locomotion; MODFETs; Power factor; Substrates; TE materials; Thermal conductivity; thermoelectric (TE) devices; Thermoelectric generators; Thermoelectricity
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2024.3412863

2-D electron gas (2DEG) is one of the promising approaches for high thermoelectric (TE) performance. However, high electrical resistance of the film originating from thin 2DEG conduction channel width and thick insulator layer is a bottleneck for obtaining high output power. In this study, we propose stacked GaAs 2DEG thermoelectric generator (TEG), which has a number of stacked channel structures for low electrical resistance. Our GaAs 2DEG TEGs with channels formed in triangular well exhibit ultrahigh TE power factor. In addition, the interfaces of the stacked 2DEG intensify phonon scatterings, resulting in the reduction of thermal conductivity. The stacked 2DEG TEGs exhibit nine times higher sheet electrical conductivity than the unstacked 2DEG one, resulting in ~7.5 times higher output power of stacked 2DEG TEGs (5.1 nW) than that of unstacked 2DEG ones. The cross-sectional TE efficiency factor of stacked 2DEG TEGs reaches <inline-formula> <tex-math notation="LaTeX">3.7~\mu </tex-math></inline-formula> W cm<inline-formula> <tex-math notation="LaTeX">^{-{2}} </tex-math></inline-formula> K<inline-formula> <tex-math notation="LaTeX">^{-{2}} </tex-math></inline-formula>. This value is the highest among various simple planar type film TEGs without cavities under the film. This TEG demonstration will open an avenue for the social application of 2DEG TEG.