Deep UV ${\rm Ta}_{2}{\rm O}_{5}$/Zinc-Indium-Tin-Oxide Thin Film Photo-Transistor

The authors report the fabrication of a deep-ultraviolet sensitive a-ZITO thin-film-transistor (TFT) with a Ta
₂
O
₅
gate dielectric. It is found that carrier mobility, threshold voltage, and sub-threshold swing are 106.2 cm
²
/Vs, 0.75 V, and 0.45 V/decade, respectively, measured in the dark. It is also found that measured current increased from 2.3 × 10
^-9
A to 7.97 × 10
^-5
A, as we illuminated the sample with λ = 250-nm UV light when V
G
is biased at 0 V. Furthermore, it is found that deep-UV-to-visible rejection ratio could reach 2.3 × 10
⁵
for the fabricated Ta
₂
O
₅
/a-ZITO TFT.