Synthesis of free-standing Ga₂O₃ films for flexible devices by water etching of Sr₃Al₂O₆ sacrificial layers

Flexible electronic devices have attracted much attention due to their practical and commercial value. Integration of thin films with soft substrate is an effective way to fabricate flexible electronic devices. Ga₂O₃ thin films deposited directly on soft substrates would be amorphous mostly. However, the thickness of the thin film obtained by mechanical exfoliation method is difficult to control and the edge of the film is fragile and easy to be damaged. In this work, we fabricated free-standing Ga₂O₃ thin films using the water-soluble perovskite Sr₃Al₂O₆ as a sacrificial buffer layer. The obtained Ga₂O₃ thin films were polycrystalline. The thickness and dimension of the films were controllable. A flexible Ga₂O₃ solar-blind UV photodetector was fabricated by transferring the free-standing Ga₂O₃ film on a flexible polyethylene terephthalate substrate. The results displayed that the photoelectric performances of the flexible Ga₂O₃ photodetector were not sensitive to bending of the device. The free-standing Ga₂O₃ thin films synthesized through the method described here can be transferred to any substrates or integrated with other thin films to fabricate electronic devices. (special topic)