High quality factor multichannel filter of electrons based on defective CdMnTe/CdTe multi-quantum wells

Abstract

Using the transfer matrix (TM) method, the propagation of electrons is studied, in a one-dimensional multi-quantum well composed of alternating layers of barriers and wells. In the first time, we proposed system with a single barrier CdMnTe is embedded between two semi-infinite substrates. Hence, the corresponding Eigen modes energies were found to be shifted towards lower energies as the barrier thickness increases. The resulting Eigen modes are characterized by a high transmission rates but a very low quality factor values, which highlight the importance of the system periodicity. On the other hand, in order to create localized states in the band gaps, a defective system is exanimated. Indeed, a defect barrier is inserted in a perfect multi-quantum wells (MQWs) system, basically made of repeated CdMnTe barriers and CdTe wells. This defective system can create multi defect modes in the electronic band gaps. The analysis of the transmittance spectra of the defect states evidences a shift to lower energies by increasing the defect thickness with fixed parameters of the system. These defect states move toward higher energy regions, when the concentration of defect increases. In addition, the energy of the defect states varying from 600 meV to 785 meV. We found one defect state for a defect concentration equal to 0.7, when the defect thickness is equal to 5 A°. Otherwise, for a defect concentration equal to 0.1, with a defect thickness of 150 A°, we found two defect states appeared inside the gaps. While, three defect states were found for a concentration interval between 0.3 and 0.5 and a defect thickness equal respectively to 127 A°and 145 A°. These defect states have higher quality factors reaching 7630000. Moreover, it shown that the number of gaps modes depends on the defect concentration's and thickness' parameters. High quality factors are reached, and an electron multichannel filtering system is then proposed.

Electron Transport in AlGaAs Cylindrical Quantum Wire Sandwiched between Two GaAs Cylindrical Quantum Well Wires

“…We can also see that when the thickness of the barrier d1 increases, the number of electronic states increase and move towards high energies. This last result is similar to the one found by Ezzarfi et al when they considered a finite CdMnTe semiconductor between two substrates of the same nature [25]. When the energy of the incident electron coincides with one of the electronic states, the electron is completely transmitted.…”

Effect of the Introduction of a Staircase Defect on the Behavior of the Induced Electronic State in a MQWs Structure

“…I. Erdogan et al [8] have studied the effect of laser field on the self-polarization of a donor impurity in a finite Ga1-xAlxAs/GaAs quantum well. Furthermore, we find other researchers who studied the band structures and even the electron transport in MQWs by determining their physical properties (transmission, reflection, dispersion relation ...) using the Green's function [9], or the transfer matrix [10]. For example, we find that A. Shokri [11] studied a periodic MQWs, composed of two alternating materials, GaAs-AlGaAs.…”

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