Simulation of relaxation times and energy spectra of the CdTe/Hg1 − x Cd x Te/CdTe quantum well for variable valence band offset, well width, and composition x

Optical transitions in Cd x Hg1 − x Te-based quantum wells and their analysis with account for the actual band structure of the material

“…The same paper reported that the valence band disconti nuity varies linearly with the composition. The above value is sometimes used in calculations even now [16]. However, according to modern data, the valence band discontinuity between HgTe and CdTe exceeds 0.5 eV [17,18].…”

Electron relaxation and mobility in the inverted band quantum well CdTe/Hg1-xCdxTe/CdTe

“…In these structures, the electron ground level always lies below the bottom of the conduction band of the well, while the first level appears inside the band gap at large widths of QW [17]. With the decrease of the QW width, the excited levels climb up, while the ground level goes deeper under the Fermi level.…”

“…Nevertheless, the k  = 0 wave functions correctly describe many principal features of the band structure under consideration, particularly, they correctly describe the localization of electrons in the well and selection rules for interband transitions. Moreover, the energy spectra obtained in terms of the envelope functions approach [17] behave in the same way as such spectra obtained in terms of the 88 kp method [37]. In our calculations, we use nonparabolic dispersion law in order to describe correctly the energy dependence of the density of states.…”

“…Thus, electron levels are located much higher than the Fermi level, and their occupancy influences the electron scattering processes only slightly. CdTe/Hg 1-x Cd x Te/CdTe QWs with the composition 0 < x < 0.16 have an inverted band scheme inside the well and a direct band scheme in barriers [15,17]. Thus in such structures there exist one or two electron levels which lie below the bottom of conduction band of the well (see Fig.…”

“…is the Fermi-Dirac distribution function for localized electrons in the QW, energy E depends on the wave-vector k via the nonparabolic dispersion law, for example in the well this law has the form [17], where P is the Kane matrix element equal to 8.310 -8 eVcm. Using the principle of detailed balance, one can obtain that…”