  We study the stationary surface photocurrent in 2D electron gas near the
helium surface. Electron gas is assumed to be attracted to the helium surface
due to the image attracting force and an external stationary electric field.
The alternating electric field has both vertical and in-plane components. The
photogalvanic effect originates from the periodic transitions of electrons
between quantum subbands in the vertical direction caused by a normal component
of the alternating electric field accompanied by synchronous in-plane
acceleration/deceleration due to the electric field in-plane component. The
effect needs vertical asymmetry of the system. The problem is considered taking
into account a friction caused by the electron-ripplon interaction. The
photocurrent resonantly depends on the field frequency. The resonance occurs at
field frequencies close to the distance between well subbands. The resonance is
symmetric or antisymmetric depending on the kind (linear or circular) of
polarization.
