For
traditional wide-bandgap semiconductor materials, a high-temperature
process is unavoidable for improving crystallization quality, so the
substrate of the device is greatly limited. In this work, zinc–tin
oxide (a-ZTO) amorphous oxide processed by the pulsed laser deposition
method was utilized as the n-type layer, which exhibits considerable
electron mobility and optical transparency, and can be deposited at
room temperature. At the same time, by combining p-type CuI grown
by the thermal evaporation method, a vertically structured ultraviolet
photodetector based on CuI/ZTO heterojunction was obtained. The detector
demonstrates self-powered properties, with an on–off ratio
exceeding 104, and rapid response with a rise time of 2.36
ms and a fall time of 1.49 ms. Also, the photodetector shows long-term
stability with 92% retention after 5000 s cyclic lighting and maintains
reproducible response in frequency dependence measurement. Furthermore,
the flexible photodetector on poly(ethylene terephthalate) (PET) substrates
was constructed, exhibiting fast response and durability in the bending
state. This is the first time that the heterostructure based on CuI
has been applied in the flexible photodetector. The excellent results
indicate that the combination of amorphous oxide and CuI has the potential
for ultraviolet photodetectors, and will broaden the application range
of high-performance flexible/transparent optoelectronic devices in
the future.