Piezoelectric gate for a two-dimensional electron system transport in LiNbO/sub 3/-GaAs/AlGaAs sandwich structures

Standing-wave piezoelectric fields in the LiNbO₃ driving plate are used to form depleted and accumulated electron densities in GaAs/AlGaAs quantum wells (QWs). The photoluminescence spectrum of the two-dimensional electron system varies both spatially and temporally, exhibiting an electron-hole plasma recombination and exciton and trion emissions at large and small electron densities, respectively. Controlling the piezoelectric field component perpendicular to the QW layers offers a versatile tool to achieve the spatially indirect exciton luminescence in double QW structures.