HIGH-DIFFERENTIAL MOBILITY OF HOT-ELECTRONS IN DELTA-DOPED QUANTUM-WELLS

Although electrons in center delta-doped AlGaAs/GaAs quantum wells have lower low-field mobilities than do electrons in uniformly doped quantum wells, experimental results presented here show that at electric fields between 2 and 4 kV/cm the differential mobility in delta-doped quantum wells rises dramatically. This large increase in differential mobility may be a result of the heating of the electrons out of the symmetric ground state into the antisymmetric first excited state. Because the excited state has a node at the delta doping, these hot electrons have a much smaller overlap with the ionized impurities of the doping spike in the well centers and therefore higher mobility.