Investigation of Nano-Gaps in Fractured β-Ga₂O₃ Nanomembranes Formed by Uniaxial Strain

A free-standing β-Ga₂O₃, also called β-Ga₂O₃ nanomembrane (NM), is an important next-generation wide bandgap semiconductor that can be used for myriad high-performance future flexible electronics. However, details of structure-property relationships of β-Ga₂O₃ NM under strain conditions have not yet investigated. In this paper, the electrical properties of β-Ga₂O₃ NM under different uniaxial strain conditions using various surface analysis methods are systematically investigated and layer-delamination and fractures are revealed. The electrical characterization shows that the presence of nanometer-sized gaps between fractured pieces in β-Ga₂O₃ NM causes a severe property degradation due to higher resistance and uneven charge distribution in β-Ga₂O₃ NM which is also confirmed by the multiphysics simulation. Interestingly, the degraded performance in β-Ga₂O₃ NM is substantially recovered by introducing excessive OH-bonds in fractured β-Ga₂O₃ NM via the water vapor treatment. The X-ray photoelectron spectroscopy study reveals that a formation of OH-bonds by the water vapor treatment chemically connects nano-gaps. Thus, the treated β-Ga₂O₃ samples exhibit reliable and stable recovered electrical properties up to ≈90% of their initial values. Therefore, this result offers a viable route for utilizing β-Ga₂O₃ NMs as a next-generation material for a myriad of high-performance flexible electronics and optoelectronic applications.