Fabrication of GaN-based MSM droplet triboelectric nanogenerator by the conjunction of photovoltaic and triboelectric effect

The present work focuses on the fabrication of Gallium Nitride based triboelectric nanogenerators for energy harvesting from moving NaCl droplets of various concentrations between 0.1 M and 1.0 M. Fabricated Droplet-Based (DB)-TENG is found to generate a voltage of ∼18.3 V, current of 0.9 µA and power of 64 µW at a load resistance of 150 MΩ by drop casting the NaCl droplet over GaN thin film. The direct growth of GaN on Aluminium Nitride over different substrate including Si(n + +), Si (100), Sapphire, and Si (111) is achieved using the Laser Molecular Beam Epitaxy technique, for the improved device performance, a substrate-dependent comparison analysis is also conducted. The effect of ultraviolet (UV) light of wavelength 325 nm on the DB-TENG has also been studied to enhance the induced signal and the maximum output voltage of ∼ 42 V, current of 8.8 µA and maximum output power of 824 µW were measured with 150 MΩ load resistance. The results indicate an enhancement in the generated voltage by 3 times and the current by one order upon UV illumination. This work is used for energy harvesting in the form of mechanical energy and photon energy by coupling the photovoltaic and triboelectric effects.