  Light-to-electricity conversion is crucial for energy harvesting and
photodetection, requesting efficient electron-hole pair separation to prevent
recombination. Traditional junction-based mechanisms using built-in electric
fields fail in non-barrier regions. Homogeneous material harvesting under
photovoltaic effect is appealing but only realized in non-centrosymmetric
systems via bulk photovoltaic effect. Here we report the realization of
photovoltaic effect by employing surface acoustic waves (SAW) to generate
zero-bias photocurrent in a conventional layered semiconductor MoSe2. SAW
induces periodic modulation to electronic bands and drags the photoexcited
pairs toward the travelling direction. The photocurrent is extracted by a local
barrier. The separation of generation and extraction processes suppresses
recombination and yields large nonlocal photoresponse. We distinguish
acousto-electric drag and electron-hole pair separation effect by fabricating
devices of different configurations. The acousto-drag photovoltaic effect,
enabled by piezoelectric integration, offers an efficient light-to-electricity
conversion method, independent of semiconductor crystal symmetry.
