The influence of an external electric field on intracenter optical transitions in semiconductor quasi-zero-dimensional structures

Background. The development of double selective doping technology has stimulated interest in the optical properties of semiconductor nanostructures containing $H^-$-like impurity centers and their molecular complexes. Interest in the optical properties of quantum dots with $D_2^-$-centers in an electric field is due, first of all, to the possibility of effectively controlling both the binding energy of impurity states and the photoexcitation spectra of molecular impurities. Depending on the radius of the quantum dot and the spatial configuration of impurity molecules $D_2^-$ the photoexcitation band can be in both the visible, IR, and terahertz frequency range, which significantly expands the range of instrumental applications of quantum dots (QDs) with impurity states. In this regard, quasi-zero-dimensional structures with $D_2^-$ impurity states, on the basis of which it is possible to create receivers in the IR and terahertz ranges, are of great interest. The purpose of this work is to theoretically study the features of the spectra of intracenter optical transitions in quasi-zero-dimensional structures with $D_2^-$-centers in an electric field. Materials and methods. The binding energy of $D_2^-$ states was calculated using the zero-radius potential method in the effective mass approximation. The expression for the coefficient of impurity absorption of light was obtained in the dipole approximation within the framework of perturbation theory. Results. It is shown that breaking the symmetry in the arrangement of $D^0$-centers leads to the removal of degeneracy between the g- and u-terms. It is shown that an external electric field leads to a decrease in the splitting between the g- and u-terms. It has been established that the photoexcitation spectrum is a band, the position of which depends on the strength of the external electric field. Conclusions. Quasi-zero-dimensional structures with $D_2^-$-centers in an external electric field can be used to create IR and terahertz detectors with controllable characteristics.ters in an external electric field can be used to create IR and terahertz detectors with controllable characteristics.