Transport and quantum lifetimes of electrons in modulation doped Al0.3Ga0.7As/In0.15Ga0.85As double quantum well structure

Modulation of electron transport and quantum lifetimes in symmetric and asymmetric AlGaAs/InGaAs double quantum well structures

“…Double quantum well (DQW) structures have attracted much interest due to their confinement as well as the tunneling coupling phenomenon. 2,[13][14][15][16][17][18] The introduction of a barrier at the center of a well leads to additional interfaces. However, as an additional parameter it can be utilized to achieve resonance of subband states (RSS) either by changing the structural parameters or by applying an external perturbation such as an electric field or magnetic field.…”

“…However, as an additional parameter it can be utilized to achieve resonance of subband states (RSS) either by changing the structural parameters or by applying an external perturbation such as an electric field or magnetic field. 13,[16][17][18] The absence of a central barrier leads to symmetric (exhibiting a maximum at the well center) and antisymmetric (with a node at the center of the well) envelope functions (ψ n ) of the ground and first excited states, respectively. The narrow barrier in the DQW structure separates the intersubband energy levels (E n ) in the QWs and changes the ground state envelope function into a doublet, which drastically changes the effect of different scattering mechanisms.…”

“…The presence of the factor 1cosθ, with θ being the scattering angle, dominates the contribution of large-angle scattering. 13) In the literature many different efforts have been made to study and analyze τ t and τ q in different III-V compound based semiconductors such as GaAs/AlGaAs [19][20][21] and AlGaN/GaN [22][23][24] QW structures. However, very few attempts have been made to study the effect of different scattering mechanisms on τ t and τ q in AlGaAs/InGaAs-based DQW structures.…”

“…However, very few attempts have been made to study the effect of different scattering mechanisms on τ t and τ q in AlGaAs/InGaAs-based DQW structures. 13,25,26) In this paper, we modulate and analyze τ t and τ q as functions of applied electric field F in Al 0.3 Ga 0.7 As/In 0.15 Ga 0.85 As-based symmetric and asymmetric DQW structures mediated by different scattering mechanisms such as ionized impurity (ii), alloy disorder (al) and interface roughness (ir). We have adopted a static dielectric response function formalism within the RPA and consider the screening of the above discussed scattering potentials by the two-dimensional electrons formed in the In 0.15 Ga 0.85 As QW.…”

“…The confinement effect splits the energy levels of electrons E n . The subband energy levels E n and their corresponding wave functions ψ n associated with the proposed structures are obtained by using the one-dimensional Schrödinger equation 13,18) ( )…”