Synthesis of free-standing Ga2O3 films for flexible devices by water etching of Sr3 Al2O6 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.