【Epitaxy Papers】Ultrafast self-powered solar blind UV photodetectors based on amorphous Ga₂O₃ thin films in crossbar geometry

      Researchers from the Raja Ramanna Centre for Advanced Technology have published a dissertation titled "Ultrafast self-powered solar blind UV photodetectors based on amorphous Ga₂O₃ thin films in crossbar geometry" in Materials Today Physics.

Abstract

      Amorphous gallium oxide (a-Ga₂O₃) based UV photodetectors combine the benefits of low growth temperature, large-area processibility and use of flexible, inexpensive substrates with performance comparable to their crystalline counterparts. Despite these advantages, their photoresponse time is notably slower. To mitigate this, ultrafast vertical Schottky type Au/a-Ga₂O₃/ITO solar blind ultraviolet photodetectors have been developed in crossbar geometry, wherein the a-Ga₂O₃ thin film, deposited by RF magnetron sputtering, is sandwiched between the bottom ITO and orthogonal top semi-transparent Au Schottky electrodes. The device sizes vary from ∼8 to 12 mm². The temporal UV photoresponse measurement of the devices at zero bias shows ultrafast response with both rise and fall times of ∼2 μs, which is the fastest reported till date for a-Ga₂O₃ based UV photodetectors. The zero bias spectral responsivity measurement reveals that the responsivity peaks at 250 nm with the cut-off at 273 nm. The maximum self-powered spectral responsivity of ∼14 mA/W obtained in these crossbar devices is comparable to that of a-Ga₂O₃ based devices reported in literature. These crossbar Au/a-Ga₂O₃/ITO devices showing ultrafast self-powered solar blind UV photoresponse are promising for applications requiring fast solar blind UV detectors such as UV communication, imaging, missile plume detection etc.

DOI：

https://doi.org/10.1016/j.mtphys.2025.102007