Intersubband electronic Raman scattering in narrow GaAs single quantum   wells dominated by single-particle excitations
  We measured resonant Raman scattering by intersubband electronic excitations in GaAs/AlAs single quantum wells (QWs) with well widths ranging from 8.5 to 18 nm. In narrow (less than 10 nm) QWs with sufficiently high electron concentrations, only single-particle excitations (SPEs) were observed in intersubband Raman scattering, which was confirmed by the well-width dependence of Raman spectra. We found characteristic variations in Raman shift and line shape for SPEs with incident photon energy in the narrow QWs. 
Takeya Unuma, Kensuke Kobayashi, Aishi Yamamoto, Masahiro Yoshita,   Yoshiaki Hashimoto, Shingo Katsumoto, Yasuhiro Iye, Yos...