Intra-center energy transfer dynamics in Cd1−xMnxTe semi magnetic semiconductors

Abstract

Intra-center luminescence of Cd1−xMnxTe semi magnetic semiconductors under low excitation density was investigated both experimentally and by Monte-Carlo simulation. Experimental time-resolved spectra of 2eV-band under different photon energy for excitation were used. The approach revealed that Mn2+–Mn2+excitation energy transfers take place by means of resonant dipole–dipole interaction. Besides energy transfer dynamics is strongly influenced by hopping-assisted quenching. Having been intra-center excitation selective-, mixed- and non-selective types of excitation are proved to occur if photon energy for excitation is increased. This is originated from overlapping of 4T1- and 4T2-states. Under inter-band excitation it was established that Mn2+-ion excitation takes place with the aid of excitonic energy transfer, with excitation energy being centered at exciton energy. Under temperature rise the transfer rate vigorously enhances due to great increase of overlap integral of Mn2+- ions' side-bands. The quenching is proved to be limited in accordance with existing theory. Inhomogeneous broadening diminishes as a result of fast fluctuation rate of excited ions' energy.