Ga₂O₃/V₂O₅ Oxide Heterojunction Photovoltaic Photodetector With Superhigh Solar-Blind Spectral Discriminability

Heterojunction photodetectors (PDs) with photovoltaic effect could play a crucial role in future energy-conservation photoelectronic devices for their self-powered work manner. Herein, a self-powered PD was successfully constructed on the all-oxide Ga
₂
O
₃
/V
₂
O
₅
thin-film heterojunction. With a type-I straddling band alignment, the Ga
₂
O
₃
/V
₂
O
₅
heterostructure demonstrated an obvious photovoltaic effect with an open-circuit voltage of 0.4 V. The large bandgap (5.01 eV) of
$\beta $
-Ga
₂
O
₃
and the effective electron–hole pair separation within heterointerface produced a superhigh solar-blind spectral discriminability for the Ga
₂
O
₃
/V
₂
O
₅
heterojunction PD, with deep-ultraviolet (DUV)/visible rejection ratio (
${R}_{{240}}/{R}_{{400}}$
) of 6.0
$\times 10^{{4}}$
, photo-to-dark current ratio (PDCR) of
$2.6 \times 10^{{7}}$
, on/off switching ratio of
$1.87\times 10^{{5}}$
, and specific detectivity of 7.8
$\times 10^{{13}}$
Jones. The largest responsivities in self-powered mode (0 V) and power-supply mode (−5 V) were 19.8 and 79.2 mA/W, respectively. The excellent self-powered photodetection performance of Ga
₂
O
₃
/V
₂
O
₅
oxide heterojunction provides a new strategy for next-generation energy-conservation solar-blind PDs.