Electron transport mobility in a δ-doped double quantum well structure

Abstract

The electron transport mobility μn in a GaAs/AlxGa1−xAs coupled double quantum well structure has been studied. The central barrier is delta-doped with Si so that we have two sheets of two dimensional electron gas separated by a positively charged donor layer. The subband electron wave functions and the energy levels are numerically obtained as a function of barrier height, barrier width, well width, and doping concentration. The screened ionized impurity potential is obtained in terms of the static dielectric response function within the random phase approximation. The effect of tunneling of electrons through the barrier, screening of ionized impurities, and intersubband scattering on μn of the double channel system is investigated. It would be interesting to compare our results for μn with experiment, when available.

Low temperature electron mobility in a coupled quantum well system

“…The intersubband scattering not only allows more scattering channels, but also affects the screened impurity potential V eff nm (q) by involving all the subbands of the system (eqn (23)). In our formulation screening of ionized impurities has been obtained by using random phase approximation (RPA), which has been proved successful for practical numerical calculations of electron transport mobility in a multisubband system [5][6][7]17]. We note that because of the finite potential barrier there will be electron penetration into it.…”

“…It is gratifying to note that the screening, which is determined by the dielectric matrix eqn (13), is also discontinuous at the higher subband occupancy and results in a discontinuous scattering matrix element which leads to an increase in the intrasubband terms, say, B 00 . In fact it has been shown that the change in B 00 is the major contribution for the drop in mobility at the onset of occupation of a higher subband [17].…”

Intersubband-coupling and screening effects on the electron subband mobility in a GaAs∕InxGa1−xAs delta-doped double quantum well system

“…In the present paper we analyze electron transport mobility in a barrier ␦-doped GaAs/ In x Ga 1−x As double quantum well structure. Unlike the GaAs/ Al x Ga 1−x As systems, [12][13][14][15] here the well region is the alloy layer ͑InGaAs͒ and hence we consider the effect of alloy disorder scattering in addition to the ionized impurity scattering for the calculation of n . The merits of GaAs/ In x Ga 1−x As strained layer 1,2 and advantages of ␦ doping in the barrier region of the heterostructure [16][17][18] have been employed to analyze n .…”

Effect of electric field on low temperature multisubband electron mobility in a coupled Ga0.5In0.5P/GaAs quantum well structure

“…The electron transport in such multisubband occupied systems has been shown to be influenced by intersubband interactions. [17][18][19][20][21][22] In a recent paper 22 we studied the effect of intersubband interaction on the subband mobility of a coupled GaInP/GaAs double quantum well structure. We showed that the intersubband interaction not only controls the effect of roughness of different interfaces but also exhibits interesting results on the well width up to which the interface roughness ͑IR͒ dominates in a double quantum well structure.…”