Fabrication of a Flexible Photodetector Based on a Liquid Eutectic Gallium Indium

A fluidic gallium-based liquid metal (LM) is an interesting material for producing flexible and stretchable electronics. A simple and reliable method developed to facilitate the fabrication of a photodetector based on an LM is presented. A large and thin conductive eutectic gallium indium (EGaIn) film can be fabricated with compressed EGaIn microdroplets. A solution of LM microdroplets can be synthesized by ultrasonication after mixing with EGaIn and ethanol and then dried on a PDMS substrate. In this study, a conductive LM film was obtained after pressing with another substrate. The film was sufficiently conductive and stretchable, and its electrical conductivity was 2.2 × 106 S/m. The thin film was patterned by a fiber laser marker, and the minimum line width of the pattern was approximately 20 μm. Using a sticky PDMS film, a Ga2O3 photo-responsive layer was exfoliated from the fabricated LM film. With the patterned LM electrode and the transparent photo-responsive film, a flexible photodetector was fabricated, which yielded photo-response-current ratios of 30.3%, 14.7%, and 16.1% under 254 nm ultraviolet, 365 nm ultraviolet, and visible light, respectively.

The Effect of Scan Speed on Engraving Depth and Surface Roughness of AISI H13 Tool Steel

The aim of this study is to investigate the effect of scan speed and frequency on surface roughness and engraving depth of AISI H13 hot work tool steel. The experimental studies were conducted by fiber laser marker machine. The relationship between the parameters is showed that the highest surface roughness and depth values were achieved at lowest scan speed (125mm/s). The depth and surface roughness of engraved geometry was decreased at increase in scan speed. It was concluded that, the surface roughness and depth can be controlled by scan speed and frequency.