О доминирующем механизме безызлучательного возбуждения ионов марганца в II-VI полумагнитных полупроводниках

Doping of group II-VI semiconductors and low-dimensional structures based on them with manganese leads to effective quenching of electro-and photoluminescence provided that the electron excitation energy of the crystal exceeds the energy of the intracenter transition of Mn2+ EMn и 2.1 eV. Quenching involves efficient energy transfer from the photoexcited crystal to Mn2 + ions. There are three possible mechanisms of this non-radiative energy transfer: dipole-dipole, exchange and related mechanism associated with sp-d mixing. Although the dipole-dipole mechanism is thought to be ineffective due to the forbidden intracenter transition in Mn2+, and the spin-dependent exchange mechanism is dominant, not all experimental facts accumulated to date supports this conclusion. The article discusses two experimental approaches to identify the dominant mechanism of energy transfer to Mn2 + ions and to evaluate the partial contributions of the mechanisms. One of these approaches is related to optically detectable magnetic resonance at single diluted magnetic semiconductor quantum dots (QD), the second - to plasmon amplification of energy transfer to Mn2 + ions by means of dipole-dipole interaction.

Synthesis and characterization of high-efficiency low-cost solar cell thin film

Polycrystalline chalcogenide semiconductors play a vital role in solar cell applications due to their outstanding electrical and optical properties. Among the chalcogenide semi-conductors, CdZnS is one kind of such important material for applications in various modern solid state devices such as solar cells, light emitting diode, detector etc. Due to their applications in numerous electro-optic devices, group II-VI semiconductors have been studied extensively. In recent years, major attention has been given to the study of electrical and optical properties of CdZnS thin films. In this work, Cd1−xZnxS thin films were prepared by chemical bath deposition technique. Phase purity and surface morphology properties were analyzed using field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) studies. Chemical composition was studied using energy dispersive spectrophotometry (EDS). Optical band gap property was investigated using UV-Spectroscopy. Electrical conductivity studies were performed by two probe method and thermoelectric power setup (TEP) to determine the type of the material. This work reports the effect of Zn on structural, electrical, microstructural and optical properties of these films.

Note on Resonant Raman Scattering in Polar Materials

The multiplicity and relative intensity of LO phonon lines observed in resonant Raman scattering experiments on Group II–VI semiconductors are analyzed in terms of a configuration coordinate model for excitons and exciton complexes.