Search

A new microwave integration technology of electroplating is proposed, which combines formation and mounting of multilayer structures. It uses a minimal amount of flanges in the waveguide communication lines for extra-high frequency (EHF), and is capable also to integrate the metallic and non-metallic parts into the waveguide structure with no detachable elements. Products’ weight and dimensions were significantly reduced while ensuring their sufficient rigidity and strength. The mechanical machining, gold and silver coatings were totally excluded; components’ and units’ parameters were improved. The settings and adjustment of the finished product were greatly simplified.

Possibilities of dramatic improvement in functionality by effects of bulk N-type Negative Differential Conductivity (N-NDC) in long inhomogeneous samples are described together with outstanding parameters of devices utilizing the effect.

Optical properties of ZnMnO layers grown at low temperature by Atomic Layer Deposition and Metalorganic Vapor Phase Epitaxy are discussed and compared to results obtained for ZnMnS samples. Present results suggest a double valence of Mn ions in ZnO lattice. Strong absorption, with onset at about 2.1 eV, is tentatively related to Mn 2+ to 3+ photoionization. Mechanism of emission deactivation in ZnMnO is discussed and is explained by the processes following the assumed Mn 2+ to 3+ recharging. © 2009 Elsevier B.V. All rights reserved.

Intra-shell transitions of transition metal and rare earth ions are parity forbidden processes. For Mn2+ ions this is also a spin forbidden process, i.e., light emission should be inefficient. Surprisingly, it has been reported that in nanostructures of ZnMnS the T14 to A16 intra-shell transition of Mn2+ results in a bright photoluminescence characterized by a short PL decay time. The model of a quantum confined atom was introduced to explain the observed experimental results. It was later claimed that this model is incorrect. Based on the results of our photoluminescence, photoluminescence kinetics, time-resolved photoluminescence, electron spin resonance, and optically detected magnetic resonance investigations, we confirm photoluminescence enhancement and decrease of photoluminescence lifetime and relate these effects to spin dependent magnetic interactions between localized spins of Mn2+ ions and spins/magnetic moments of free carriers. This mechanism is active in both bulk and in low-dimensional structures, but is significantly enhanced in nanostructure samples. © 2007 American Institute of Physics.

Bulk samples, layers, quantum well, and quantum dot structures of II-Mn-VI samples all show coexistence of slow and fast components of Mn2+ photoluminescence decay. Thus, fast photoluminescence decay cannot be related to low dimensionality of a host material. This also means that the model of the so-called quantum confined atom is incorrect. Based on the results of time-resolved photoluminescence and optically detected magnetic resonance investigations we relate the observed lifetime decrease in Mn2+ intra-shell transition to spin dependent magnetic interactions between localized spins of Mn2+ ions and between Mn2+ ions and spins/magnetic moments of free carriers. The latter mechanism is enhanced in nanostructures.

Based on the results of optically detected magnetic resonance (ODMR) and time-resolved investigations we relate the observed lifetime shortening of intra-shell Mn2+ emission to spin dependent magnetic interactions between localized spins of Mn2+ ions and spins/magnetic moments of free carriers. We show that this mechanism is active both in bulk and in low dimensional structures, such as quantum wells (QWs), quantum dots (QDs) and nanostructures. (C) 2004 Elsevier B.V. All rights reserved.

In this work we employ technique of optically detected cyclotron resonance for evaluation of the role of localization processes in CdTe/CdMnTe and CdMnTe/CdMgTe quantum well structures. From microwave-induced changes of excitonic emissions we evaluate magnitude of potential fluctuations (Stokes shift), correlate optically detected cyclotron resonance results with the results of time-resolved experiments and discuss nature of recombination processes in the limit of a strong localization.

The spin dependent interactions of free carriers and manganese ions in nanostructures of wide band gap were discussed. The observed lifetime shortening of intrashell manganese ion emission was related to spin dependent magnetic interactions. The mechanism was found to be active in both bulk and low dimensional structures.