22 research outputs found
Einfluss thorakaler Epiduralanalgesie (TEA) auf die Inzidenz postoperativer Nachbeatmung bei Patienten mit Myasthenia gravis
Doping of the Wide-Gap Semiconductor CdMgTe During Molecular Beam Epitaxy
We investigated the n-type doping of the wide-gap II-VI semiconductor (CdMg)Te. The n-type doping of (CdMg)Te has previously been achieved in only a small range of magnesium concentration. By the use of zinc iodine as dopant source material, we obtained highly doped (CdMg)Te layers up to a magnesium concentration of 40%. The limiting factor for the free carrier concentration at room temperature is the occurrence of a deep level, which dominates the electrical properties at room temperature of layers with more than 30% magnesium. Compensating defects or defect complexes are considered, to explain the observed properties of the deep level, which do not seem to be characteristic of an isolated donor state
Exciton States in Type-II ZnSe/BeTe Quantum Wells
We present an optical investigation of novel heterostructures based on beryllium chalcogenides with a type-I and type-II band alignment. In the type-II quantum well structures (ZnSe/BeTe) we observed a strong exciton transition involving an electron confined in the conduction band well and a hole localized in the valence band barrier (both in ZnSe layer). This transition is drastically broadened by the temperature increase due to enhanced exciton-acoustic phonon interaction