Metal-semiconductor direct-current triboelectric nanogenerator based on depletion mode u-GaN/AlGaN/AlN/GaN HEMT

Abstract

The urgent need for renewable energy source has led to a significant interest in triboelectric nanogenerators (TENGs) as a new energy technology. In contrast to traditional polymer TENGs, semiconductor direct-current TENGs are more suitable for miniaturization and integration with electronic devices. This study proposes a friction material made of depletion mode GaN high electron mobility transistors (HEMTs), which exhibit superior properties such as high two-dimensional electron gas concentration. By sliding a titanium sheet on a depletion mode GaN-based heterostructure, we have designed a metal-semiconductor direct-current triboelectric nanogenerator that achieved voltage up to 45.5 V and a peak power density of 2.32 W/m2. This generator can be used to supply DC power to 14 LEDs in series and drive a digital watch directly. In particular, the generation of direct current is predominantly influenced by the surface states of the undoped GaN cap that produce a large number of electrons and are associated with an additional electric field in the direction of the two-dimensional electron gas created in the u-GaN/AlGaN/AlN/GaN heterostructure of depletion mode GaN-based HEMTs. This research not only introduces a nitride semiconductor material of GaN-based HEMTs for the metal-semiconductor interface friction in the DC TENGs but also elucidates the current generation mechanism of GaN-based HEMT TENGs.