Type-II diluted magnetic semiconductor ZnMnTe quantum dots ͑QDs͒ in ZnSe matrix grown by molecular beam epitaxy were investigated by conventional and magnetophotoluminescence ͑PL͒ spectroscopy. The QD emission exhibits a type-II characteristic in excitation power dependence of PL peak energy. A nonzero circular polarization of PL at the absence of magnetic field was observed. This phenomenon is attributed to the accumulation of interface charges confined in adjacent layers. The magneto-optical measurement demonstrates a magnetic-induced degree of circular polarization in the PL spectra, indicating the Mn incorporation into the QD system.

Articles you may be interested inDual mode operation of bistable chiral splay nematic liquid crystal cell using horizontal switching for dynamic operation J. Appl. Phys. 105, 074508 (2009); 10.1063/1.3103769 Dynamic switching behavior of bistable chiral-tilted homeotropic nematic liquid crystal displays Crucial influence on d ∕ p range in bistable chiral tilted-homeotropic nematic liquid crystal cells Reflective mode of a nematic liquid crystal with chirality in a hybrid aligned configuration

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In this paper, we report the thermally induced light leakage in in-plane-switching liquid crystal displays (IPS LCDs) that have a built-in small-angle deviation (<4 deg) between the polarization axis of a polarizer and the rubbing directions for liquid crystal (LC) alignment. We have found that the thermally induced light leakage depends strongly on the phase retardation which is a function of cell gap, wavelength, and birefringence of LCs used in the IPS LC cells. In addition, we have measured the light leakage of vertically aligned LC cells, which is independent of temperature and the deviation angle. A temperature-scanning method is proposed to reduce the light leakage of the IPS LCDs.

The switching behaviors of dual frequency liquid crystals (DFLC) in a bistable chiral tilted-homeotropic nematic (BHN) LC cell are simulated and compared with the observed results. This cell can be switched between tilted-homeotropic state and twisted state under the applied voltage as low as 5V. The reason for the low switching voltage is attributed to the dielectric anisotropy character of DFLC. The analysis also shows that the switching wave form accelerates the switching behaviors of the directors which results in faster response in BHN LC cell.