Ion-implanted gallium oxide for small-field beam dosimetry

Monoclinic -Ga₂O₃ has been attracting renewed interest due to its compelling properties such as its wide bandgap (~4.8 eV at room temperature) and high breakdown electric field (~8 MV/cm), which make it suitable for multiple applications, ranging from gas detectors to power electronics. In the case of optical applications, because of its high transparency, many different optical centres may be exploited, with emissions spanning the spectral region from the ultraviolet down to the near-infrared.

For instance, the Cr3+ red/nearinfrared emission in -Ga₂O₃ has been studied for its potential for ionising radiation detection in the context of optical in-vivo dosimetry. Moreover, thanks to the (100) easy-cleavage plane, it is possible to produce thin flakes by conventional mechanical exfoliation approaches, such as the scotch tape method; in spite of being useful for fast prototyping, these techniques lack reproducibility and control.

Recently, we developed an innovative process for the fabrication of single-crystalline -Ga₂O₃ microtubes and nanomembranes based on ion implantation. Additionally, this process allows the tailoring of their opto-electrical properties in the same step, thus contributing to its scalability for future industrial applications. In this context, this project aims at establishing a doping and strain engineering strategy to produce and to tune the properties of -Ga₂O₃ nanomembranes for applications in small-field beam dosimetry.

The fundamental physical processes underlying this innovative processing technology are currently under investigation by applying a powerful combination of experimental material characterisation and computational techniques, including Rutherford Backscattering Spectrometry and X-ray Diffraction, as well as Molecular Dynamics simulations. The produced membranes will then be used to develop radiation detectors, to be tested and characterised as active and/or passive dosimeters for smallfield beam