Active electronics are usually composed of semiconductor and metal electrodes which are connected by multiple vacuum deposition steps and photolithography patterning. However, the presence of interface of dissimilar material between semiconductor and metal electrode makes various problems in electrical contacts and mechanical failure. The ideal electronics should not have defective interfaces of dissimilar materials. In this study, we developed a novel method to fabricate active electronic components in a monolithic seamless fashion where both metal and semiconductor can be prepared from the same monolith material without creating a semiconductor–metal interface by reversible selective laser-induced redox (rSLIR) method. Furthermore, rSLIR can control the oxidation state of transition metal (Cu) to yield semiconductors with two different bandgap states (Cu₂O and CuO with bandgaps of 2.1 and 1.2 eV, respectively), which may allow multifunctional sensors with multiple bandgaps from the same materials. This novel method enables the seamless integration of single-phase Cu, Cu₂O, and CuO, simultaneously while allowing reversible, selective conversion between oxidation states by simply shining laser light. Moreover, we fabricated a flexible monolithic metal–semiconductor–metal multispectral photodetector that can detect multiple wavelengths. The unique monolithic characteristics of rSLIR process can provide next-generation electronics fabrication method overcoming the limitation of conventional photolithography methods.

Conclusion

We presented rSLIR as the first technology to obtain a monolithic CuNW, Cu₂ONW, and CuONW network with a seamless interface. The conventional thermal oxidation method hinders selective patterning due to heat spreading, and it is incompatible with heat-susceptive substrates. Apart from other methods, our work achieved mask-less in situ oxidation state control under low temperature and ambient conditions. Moreover, this method induces the desired oxidation state regardless of the original state, restoring conductivity or imparting functionality. Experimental and theoretical analyses verified patterning performance and the Cu₂O to CuO oxidation mechanism. A single nanowire with triple oxidation states indicates that rSLIR is a promising substitute for photolithography. Finally, rSLIR can be used to fabricate visible light photodetectors that generate varying photocurrents in accordance with wavelength and intensity. In this respect, our method works for controlling the electrical properties of transition metals. Thus we expect this technology to be exploited in various thin-film electronic devices.