The dependences of the transport scattering time τ_t, quantum lifetime τ_q, and their ratio τ_t/τ_q on the density n_e of the electron gas in modulation-doped single GaAs quantum wells with AlAs/GaAs short-period super-lattice barriers are investigated. The experimental dependences are explained in terms of electron scattering by remote ionized donors with an effective two-dimensional concentration n ^*_R and background impurities with a three-dimensional concentration n_B. An expression for n ^*_R (n_e) is obtained including the contribution of X-valley electrons localized in AlAs layers to the suppression of scattering by the random potential of remote donors. It is shown that the experimentally observed abrupt increase in τ_t and τ_q with an increase in n_e above a certain critical value n_ec is related to a decrease in n ^*_R . It is established that the drop in τ_t/τ_q observed for electron densities n_e > n_ec occurs because scattering by the random potential of background impurities in this two-dimensional system with a decrease in n ^*_R limits an increase in τ_t more considerably than an increase in τ_q.

的传输散射时间τ的相关性_吨，量子寿命τ _q，和它们的比值τ_吨/τ _q的密度Ñ _Ë电子气的在调制掺杂单个GaAs量子井的AlAs /砷化镓短周期超晶格障碍进行了调查。实验依赖性是通过有效二维浓度n ^* _R的远程电离施主的电子散射和三维浓度n _B的背景杂质的电子散射来解释的。用于表达Ñ ^* _{- [R} （Ñ _Ë ）包括在AlAs层中定位的X谷电子对远程施主的随机势能对散射抑制的贡献。结果表明，在τ实验观察到的急剧增加_吨和τ _q的增加Ñ _ë高于某一临界值Ñ _EC被在相关的降低Ñ ^* _{- [R} 。已经确定，在τ下降_吨/τ _q为电子密度观察Ñ _Ë > Ñ _{Ë Ç} 的发生是因为由本底杂质的随机电势在该二维系统，具有减少散射Ñ ^* _{- [R}限制了τ的增加_吨比更为显着地增加了τ _q。