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

Abstract

Background. The development of double selective doping technology has stimulated interest in the optical properties of semiconductor nanostructures containing H(-)-like impuritycenters and their molecular complexes. Interest in the optical properties of quantum dots with D2− -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 D2− the photoexcitation band can be in both the visible, IR, and terahertz frequency range, which significantly expands the range of instrumental applications ofquantum dots (QDs) with impurity states. In this regard, quasi-zero-dimensional structures with D2− 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 thefeatures of the spectra of intracenter optical transitions in quasi-zero-dimensional structures with D2− centers in an electric field. Materials and methods. The binding energy of D2− 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 breakingthe symmetry in the arrangement of D0 -centers leads to the removal of degeneracy betweenthe 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 aband, the position of which depends on the strength of the external electric field. Conclusions. Quasi-zero-dimensional structures with D2− -centers in an external electric field can be used to create IR and terahertz detectors with controllable characteristics

Keywords

• terahertz radiation
• terms of impurity molecular ion
• d2− -center
• quantum dot
• quasi-zero-dimensional structure
• photoexcitation d2− -center
• impurity light absorption coefficient
• external electric field