Optical gain of Cd_xZn_1−xTe quantum dot structures

Abstract

Gain spectra of undoped and doped quantum dot (QD) structures are studied under the inhomogeneous broadening assumption at four mole fractions . For the QD structure, two peaks appear due to the excited state (ES) and ground state (GS) transitions. The gain for the doped structures doubles the undoped ones. The gain increases while the wavelength is reduced with increasing Cd content due to the broader band discontinuity between the QD states. The discontinuity of the bands for each structure (mole fraction) is calculated, which is one of the merits of this work. While the structure offers the peak wavelengths 470 and 630 nm, other mole fractions offer the wavelengths between them. These visible bands are essential in different applications. The effect of QD size effect is also examined. The wavelength is extended by 20 nm for each 1 nm QD height increment.