  Traditionally, photodetector is based on solid materials constructed PN
junction, which needs many delicate growth technologies. Herein, we demonstrate
the feasibility of polarized liquid triggered photodetector where the liquid is
sandwiched between P-type or N-type semiconductor which can be chosen freely
according to the requirement of the specific response wavelength. Under the
multiple cycles of optical switching, transient photo-polarized current, steady
state photo-polarized current and depolarized current are repeatably observed
in semiconductor/polar liquids/semiconductor structure. The responsivity and
specific detectivity of transient photo-polarized current in N-GaN/water/P-GaN
reach values of 104.2 mA/W and 4.4*10^12 Jones at 365 nm, and 52.8 mA/W and
1.9*10^12 Jones at 254 nm illumination under zero voltage bias. We anticipate
that our research will have a profound impact on integrating self-powered
photodetector with freely selectable wavelength bands.
