Fundamental Experiment of Micro Thermionic Power Generator with Narrow Gap

Abstract

In this research we fabricated a thermionic power generator with 10 µm gap. The thermionic power generator has an emitter and a collector. The emitter and the collector are separated with the gap via insulation spacers. A Si wafer coated by a W thin film was used as the emitter, and a Pt-coated Si wafer was used as the collector substrate. The thermionic power generator placed in a vacuum chamber, Cs gas was introduced to the chamber to enhance emission and its output characteristics are evaluated. When the emitter with an area of 25 mm² is heated to about 980°C by lamp heater, and temperature of the collector increases at 440°C. A maximum output of about 1.3 mW is obtained when a load resistance of 11.1 Ω is connected to the output terminal. The theoretical output of this thermionic power generator is calculated to be about 2 W. The experimental efficiency of the thermionic power generator is about 0.01%.