PHOTOINDUCED ELECTRON COUPLING IN DELTA-DOPED GAAS IN0.18GA0.82AS QUANTUM-WELLS/

We have measured the Shubnikov-de Haas (SdH) effect on delta-doped GaA s/In0.18Ga0.82As quantum wells for the magnetic field up to 12 T at th e temperature of 1.2 K. We found two SdH oscillations due to the lowes t two subbands in the In0.18Ga0.82As well with the electron densities of 14.12 and 11.02X10(11) cm(-2) and the parallel conduction due to th e electrons of about 4.86 x 10(11) cm(-2) in the V-shaped potential we ll. After the illumination of the sample for different time periods, t he electron densities of the two subbands oscillate, and the amplitude of SdH oscillation for E(0) increases but that for E(1) decreases. We believe that the reduction of SdH oscillation for E(1) is due to the electron coupling with E(delta) when the V-shaped potential well is lo wered by the illumination. In addition, the intersubband scattering be tween E(0) and E(1) becomes less important than screening effect for E (0) when E(delta) coupled with E(1).