Recently, codes over some special finite rings especially chain rings have been studied. More recently, codes over finite non-chain rings have been also considered. Study on codes over such rings or rings in general is motivated by the existence of some special maps called Gray maps whose images give codes over fields. Quantum error-correcting (QEC) codes play a crucial role in protecting quantum ...

The composition and size of optically active CdxZn1KxSe/ZnSe quantum dots are estimated with a previously developed method. The results are then compared with those obtained for CdxZn1KxSe/Zn0.97Be0.03Se QDs. We show that introducing Be into the barrier material enhances both Cd composition and quantum size effect of optically active quantum dots. q 2005 Elsevier Ltd. All rights reserved. PACS:...

The size and chemical composition of optically active CdZnSe/ZnSe and CdZnSe/Zn0.97Be0.03Se quantum dots (QDs) are determined using photoluminescence, photoluminescence excitation and polarized Raman scattering spectroscopies. We show that the addition of Be into the barrier enhances the Cd composition and the quantum size effect of optically active QDs. Additionally, surface phonons from QDs a...