Collective behavior of interwell excitons in GaAs/AlGaAs double quantum wells

Photoluminescence spectra of interwell excitons in double GaAs/AlGaAs quant um wells (n-i-n structures) have been investigated (an interwell exciton in these systems is an electron-hole pair spatially separated by a narrow AlA s barrier). Under resonance excitation by circularly polarized light, the l uminescence line of interwell excitons exhibits a significant narrowing and a drastic increase in the degree of circular polarization of photoluminesc ence with increasing exciton concentration. It is found that the radiative recombination rate significantly increases under these conditions. This phe nomenon is observed at temperatures lower than the critical point and can b e interpreted in terms of the collective behavior of interwell excitons. (C ) 2000 MAIK "Nauka/Interperiodica".