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The properties of an electron-beam-pumped ZnSe-based laser array consisting of 6 one-dimensional arrays, each comprising 10 single laser elements, have been studied. The peak output power up to 80-100 W at room temperature in 'true' green ( λ = 547 nm) spectral range has been demonstrated by using for pumping electrons with the accelerating energy as low as 5.6 keV. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

We report on the formation of Tamm plasmon (TP) modes in the visible spectral region at the interface between a Ag film and a ZnSe-based distributed Bragg reflector (DBR). The tuning of the TP eigenenergies within the stop-band in dependence on the DBR top layer thickness is investigated by micro-reflectivity measurements. The experimental findings are compared with calculations using the transfer matrix method. The latter calculations show that strong coupling can be achieved between quantum well (QW) excitons and the TP modes. In addition, the Rabi-splitting energy can be enhanced in a simple TP structure by increasing the number of QWs inside the top layer of the DBR. When a metal layer is deposited on a cold MC sample, micro-reflectivity spectra show a blue shift of the cavity resonance. The TP modes are likewise observed in the same MC sample when reducing the top layer thickness of the DBR. This shift of cavity resonance and formation of TP mode are in good agreement with calculations. These results are rather promising in order to realize a spatial confinement of the polaritons by utilizing metal strips. Such channeling of polaritons opens the way to practical demonstration of exciton-polariton integrated circuits. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

In this work, zinc selenide (ZnSe) thin films were deposited by thermal evaporation method using pure elemental (Zn and Se) sources. The physical properties of the films have been investigated in terms of the structural and optical characterizations depending on the post-annealing process under nitrogen atmosphere in the temperature between 300 and 500 °C for 30 min. The structural and compositional analyses were carried out by means of X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The compositional analysis indicated that the deposited films were nearly stoichiometric whereas there was a decrease in Se and increase in the Zn contents. This implies the segregation and/or reevaporation of Se atoms from the thin film structure. The optical characteristics were studied by using the room temperature transmission measurements. The analysis of transmission values showed that the band gap values changed in between 2.38 and 2.62 eV depending on the annealing temperatures. [ABSTRACT FROM AUTHOR]

Substrates of II-VI semiconductor compounds may be widely used in fabrication of nanoporous matrices (NM), which give the possibility to obtain nanowires and nanotubes of various materials with good application prospects in various fields. The easiest and cost-effective method to obtain nanoporous matrices is electrochemical etching (ECE), which, however, depends on conductive properties of the substrates. The conditions of growing homogeneous ZnSe, ZnS, ZnSSe, ZnO, and ZnCdS single crystals by physical and chemical vapour transport methods are discussed. Based on the results of investigation of electrical, optical, and photoluminescence properties of the samples with various doping levels, the prospect of examined technology for manufacturing the substrates of these compounds with large area and controlled n-type electrical conductivity varied up to 20, 0.3, 0.3, 9, and 30 Ω-1cm-1, respectively, is estimated. Possible utilization of these substrates for preparation of NM by ECE is analyzed. The results of nanostructuring using various electrolytes are shown. The prospect of using ZnSe and ZnCdS compounds for manufacturing nanopore arrays with diameter down to 30 nm and nanopo-rous structures with a specific morphology on ZnO substrates is demonstrated. Technological limitations for fabrication of the similar structures on the basis of ZnS and ZnSSe substrates are also analyzed. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Microcavity structures which consist of a cavity formed by two distributed Bragg reflectors can be used to study light-matter interaction in the weak and strong coupling regime. In this contribution microcavities with one or three ZnSe quantum wells embedded into the cavity are presented. In contrast to the sample with the single quantum well, strong light-matter coupling can be observed for that one with three quantum wells. The sample possesses an energy splitting of about 19meV between the upper and lower polariton branch observed by reflectivity measurements. In addition, the transition from strong to weak coupling and the starting of the photonic lasing is demonstrated by excitation density dependent measurements. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

ZnO thin films were grown by plasma-assisted MBE on GaAs substrates with ZnSe buffer layers. GaAs with different orientations: (001), (111) A, and (111) B were investigated. X-ray diffraction measurements showed that ZnO grown on (111) B GaAs substrates have the best structural quality. All the samples showed good optical qualities as indicated by room temperature photoluminescence measurements. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Photoluminescent and optical properties of ZnSe crystals doped with Yb and Gd rare-earth elements (REEs) and Cr impurity are investigated in infrared (IR) spectral range. The influence of stoichiometric deviation on photoluminescence (PL) spectra of the crystals is investigated and the structure of complex IR PL bands is analysed. The good coincidence between the IR PL spectra of the samples doped with Yb, Gd, and Cr is shown. Correlation between the component parts of the bands at 1 and 2 µm is found and possibility to control the composition of IR PL spectra by enrichment of the samples with Zn or Se is discussed. The model that explains the formation of associative centres based on the REEs and background Cu impurity fixed in the nodes of crystal lattice with tetrahedral symmetry, which are responsible for IR PL bands, is proposed. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Optically pumped green-emitting (545-551 nm) ZnSe-based laser heterostructures grown by molecular-beam epitaxy have been elaborated and studied. The optimized II-VI laser heterostructure involves a non-symmetrical Zn(Mg)SSe/ZnSe superlattice (SL) graded-index waveguide and an active region comprising five CdSe quantum dot sheets each placed in the centre of a 2 nm-thick ZnSe quantum well. Such a structure design provides both large optical confinement factor and high homogeneity of excitation. Internal laser parameters were determined by measuring the laser threshold and differential quantum efficiency as functions of the cavity length. The values of internal quantum efficiency, internal optical losses, characteristic gain and transparency threshold have been estimated to be ηi = 80.5%, αi = 3.2 cm-1, ΓG0 = 135 cm-1, and IT = 1.35 kW/cm2, respectively. Based on the defined parameters, the values of minimum threshold power and corresponding optimum cavity length have been derived. It is shown that the minimum threshold power decreases significantly (by more than 20%) in comparison with that for the heterostructure with conventional flat-band SL waveguide (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]