Miniband Electroconductivity in Superlattices of Cubic Quantum Dots of the InAs/Ga_xIn_1-xAs Heterosystem

<span>In this paper, the model of InAs/Ga</span>_x<span>In</span>_1-x<span>As cubic quantum dot superlattices (CQDS) of various dimensionality has been proposed. The energy spectra of electrons and holes of the quantum dot superlattice have been determined in the effective mass approximation and modified Kronig-Penney model. In the frame of this model, the spectra of charges of 3D, 2D and 1D-superlattices can be obtained by changing respective distances between the elements of the superlattice. The energy dependence of the electron and hole subbands (under-the-barrier subbands and over-the-barrier subbands) on the wave vector of the superlattice has been calculated. The number of under-the-barrier subbands is determined by QD size and width of each subband is defined by QD size, distances between superlattice elements and subband numerical index. The dependences of the Fermi energy and concentration of charge carriers on temperature, concentration of impurities, energy of impurity levels have been obtained and analyzed. We have taken account of the dependence of electron relaxation time on temperature caused by scattering of carriers on both phonons and donor centers. The effect of the impurity system on electroconductivity of the CQDS is investigated. It has been shown that in the presence of deep impurities (-750 meV) the temperature dependence of conductivity of the superlattice has characteristic peaks, which are defined by concentrations of impurities and dimensionality of the superlattice. A different temperature dependence of conductivity has been observed for impurities with the energy of occurrence -150 meV. </span><br /><strong>Key words:</strong><span> quantum dot, superlattice, electronic states, miniband, electroconductivity.</span>