Transferable Ga₂O₃ Membrane for Vertical and Flexible Electronics via One-Step Exfoliation

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Technology

Background:

• Gallium Oxide (Ga2O3) thin films are crucial for advanced electronics and photonics.
• Traditional growth methods on rigid substrates limit Ga2O3's application in flexible and wearable devices.
• Strong substrate-film bonds hinder the exfoliation process for versatile device configurations.

Purpose of the Study:

• To develop a transferable Ga2O3 thin film membrane for flexible and vertical electronic applications.
• To overcome the limitations of rigid substrates in Ga2O3 epitaxy.
• To enable the fabrication of novel Ga2O3-based devices for emerging technologies.

Main Methods:

• Utilizing mica as a substrate for van der Waals (vdW) epitaxy of Ga2O3.
• Employing a straightforward exfoliation technique facilitated by the weak vdW bond between Ga2O3 and mica.
• Transferring exfoliated Ga2O3 membranes to flexible adhesive tape.
• Fabricating vertical photodetectors using the transferred Ga2O3 membranes.

Main Results:

• Successful exfoliation and transfer of both thick (∼380 nm) and thin (∼95 nm) κ-phase Ga2O3, as well as conductive n-type β-Ga2O3.
• Fabrication of vertical photodetectors with peak response at ∼250 nm.
• Demonstration of self-powered photodetection with a responsivity of 17 mA/W under zero bias using integrated Ti/Au and Ni/Ag electrodes.

Conclusions:

• The vdW-bond-assisted exfoliation method provides a viable route for producing transferable Ga2O3 membranes.
• This technique opens new avenues for realizing vertical and flexible Ga2O3 electronics.
• The developed method is consistent and reproducible for various Ga2O3 film types and thicknesses.