Abstract:
Solar-blind photodetectors are critically important for civil and military applications. Several of these applications, such as space exploration
and nuclear energy infrastructure, demand the use of a photodetector under extreme environments. In this paper, we have studied the radiation
hardness and device performance of amorphous and polycrystalline gallium oxide thin films against heavy ion (Ag7+) irradiation with
a high energy of 100 MeV. Gallium oxide thin films show great tenacity against massive and highly energetic ions. The amorphous and polycrystalline
phases undergo structural and morphological changes that initially induce degradation in the device performance. Nano-pore
like structures are formed in the amorphous film, while the polycrystalline film shows the destruction of large crystallites. The responsivity
of the photodetector device reduces fourfold in the amorphous phase; however, a sixfold reduction in the performance is observed in the
polycrystalline phase of the gallium oxide photodetector. The degradation is attributed to the annealing of pre-existing optical defects that
are otherwise responsible for the huge photoconductive gain in the detector and confirmed by photoluminescence studies. The effect of
self-annealing at room temperature and annealing at moderate temperature is investigated to recover the irradiated photodetector devices.
Partial recovery in the polycrystalline based photodetector and two orders of magnitude enhanced responsivity and an almost twice faster
response time compared to the control photodetectors in the amorphous phase are observed. This work investigates the effect of heavy
and energetic ions on the performance of gallium oxide based solar-blind photodetector and provides the guideline to use high energy
irradiation as a tool for defect engineering.
