Laser Direct Writing of Sol-Gel-Derived Vacancy-Rich Functional Oxide Semiconductors.

Fabricating micro/nanostructures of oxide semiconductors with oxygen vacancies (OVs) is crucial for advancing miniaturized functional devices. However, traditional methods for the synthesis of semiconductor metal oxides (SMOs) with OVs usually involve thermal treatment, such as annealing or sintering, under anaerobic conditions. Herein, a multiphoton-induced femtosecond laser (fs) additive manufacturing method is reported for directly writing micropatterns with high resolution (∼1 μm) and abundant OVs in an atmospheric environment at room temperature (25 °C). The interdigitated functional devices fabricated by these micropatterns exhibit both photosensitivity and gas sensitivity. Additionally, this method can be applied to flexible and rigid substrates. The proposed method realizes the high-precision fabrication of SMOs with OVs, enabling the future heterogeneous integration of oxide semiconductors on various substrates, especially flexible substrates, for various device applications, such as soft and wearable electronics/optoelectronics.