Design of electrical pathways on insulator materials by laser processing

Abstract

The application of laser technology for surface modification is well known in several application fields, with very high versatility. In this work, the viability of using laser irradiation to promote electrically conductive pathways on the surface of insulator materials is demonstrated. This was performed through the laser-induced conversion of hematite (α-Fe2O3) into magnetite (Fe3O4). The results show the optimal feed rates and laser powers that promote larger magnetite pathway widths, depths and grain sizes and therefore higher electrical conductivity. The optimization of the laser processing parameters allowed magnetite pathway widths of 218 ± 8 µm and depths of 66 ± 2 µm. The electrical conductivity measurements of the irradiated regions, confirmed the effectiveness of the laser surface treatment to promote the local phase transformation of hematite into magnetite. A maximum conductivity of 1062 ± 6 mS/m was reached for a laser power of 90 W, which corresponds to the highest magnetite grain size. The results evidence the ability of laser technology to transform an electric insulator phase (α-Fe2O3) into a conductive material (Fe3O4), being possible to promote a localized electrical pathway. This study allows foreseeing applications in other oxide systems to promote localized electrical pathways on insulator surfaces, to be applied as future ceramic sensors.