Magnetron sputtering of liquid metals to quickly fabricate gallium-based nano electronic and semiconducting films

Gallium-based (Ga-based) thin films have a great number of applications in sensors, ultraviolet light electronics and semiconductors. However, the high surface tension of Gallium-based liquid metals (GBLM) makes it difficult to quickly fabricate into various nano functional films. To address this important issue, a reusable liquid metal target for magnetron sputtering were prepared, and Gallium-based liquid metals thin films and Ga/In oxide films were successfully synthesized. The average film deposition rate was realized as V ≈ 16 nm/min. The Gallium-based liquid metals film consisting of gallium and indium metals has minimum transmittance about 0.5 % and maximum reflectivity above 70 % in the visible range, and a resistivity of about 595.7 ± 42.2 Ω • cm. Further, considering the wide applications of Ga/In oxides in the fourth generations high power semiconductor devices, Ga/In oxide films were obtained by annealing the liquid metal ones at 400 ℃, which own an n-type semiconductor with optical band gap of approximately 4.37 eV. To better understand the process, the liquid phase sputtering and deposition mechanisms of liquid metal thin films in silicon and glass substrates were disclosed. Overall, with the sputtering time increasing, liquid metal nano-droplets make the hill-like continuous films deposited, which also leads to the formation of a hill-like structure with Ga2O3 shell and In2O3 inner core over the whole process. Magnetron sputtering based on the novel liquid metal targets provides a novel and convenient route to prepare Ga-based functional films. This method is expected to have broad values in the fields of flexible electronics and wide band semiconductors.