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The photoluminescence (PL) characteristics of GaAsSbN/GaAs epilayers grown by molecular beam epitaxy (MBE) are carefully investigated. The results show that antimony (Sb) incorporation into GaNAs material has less influence on the N-induced localization states. For the same N concentration, GaAsSbN material can reach an emission wavelength near 1.3μm more easily than GaInNAs material. The rapid thermal annealing (RTA) experiment shows that the annealing induced rearrangement of atoms and related blueshift in GaAsSbN epilayers are smaller than those in GaNAs and GaInNAs epilayers. The GaAsSbN material can keep a longer emission wavelength near 1.3μm-emission even after the annealing treatment. Raman spectroscopy analysis gives further insight into the structure stability of GaAsSbN material after annealing. [Copyright &y& Elsevier]

The structural and optical properties of MBE-grown GaAsSb/GaAs multiple quantum wells (MQWs) as well as strain-compensated GaAsSb/GaAs/GaAsP MQWs are investigated. The results of double crystal X-ray diffraction and reciprocal space mapping show that when strain-compensated layers are introduced, the interface quality of QW structure is remarkably improved, and the MQW structure containing GaAsSb layers with a high Sb composition can be coherently grown. Due to the influence of inserted GaAsP layers on the energy band and carrier distribution of QWs, the optical properties of GaAsSb/GaAs/GaAsP MQWs display a lot of features mainly characteristic of type-I QWs despite the type-II GaAsSb/GaAs interfaces exist in the structure. [Copyright &y& Elsevier]

Abstract In order to investigate the grain size effect on the electrical conductivity of the submicron samarium-heavily-doped ceria, the Ce 0.8 Sm 0.2 O 1.9 (SDC20) ceramics with grain sizes from 128 nm to 533 nm were prepared by sintering at 1000–1300 °C in the air atmosphere. The crystalline structure, micro-morphology, density and electrical conductivity of the SDC20 ceramics were measured and characterized by XRD, SEM, TEM, Archimedes method and electrochemical impedance spectrum, respectively. All the sintered samples show the single SDC phase, low porosity and clean grain boundary without any impurities. The grain sizes of SDC ceramics grow continuously with the rising sintering temperature, and the relative densities increase as the sintering temperature rises from 1000 °C to 1200 °C and then decrease with the temperature from 1200 °C to 1300 °C. The specific grain boundary conductivity of SDC keeps decreasing while the grain and apparent grain boundary conductivities increase during the whole grain size range of 128–533 nm. [ABSTRACT FROM AUTHOR]

Solid-state tellurium (Te) is used as an n-type dopant of AlInP grown by molecular beam epitaxy (MBE). The carrier concentration proportionally increases with increasing Te beam equivalent pressure (BEP) up to a high doping density of 1×10 19 cm −3 . The incorporation of Te into AlInP results in a mirror-like surface at a moderate doping density due to its surfactant effect, while the surface roughness increased with a further rising of Te doping concentration. Furthermore, for the same In and Al flux ratio, the increase of the Te flux leads to a decreased In-content, but little effect on the alloy׳s disorder is observed. The highly Te-doped AlInP was used in a GaAs solar cell as a window layer. As compared with the solar cell with the Si-doped AlInP window layer, the device with the Te-doped AlInP window layer exhibits the higher efficiency and an extended increase under concentrated solar illumination, due to the benefits of the higher doping density in the Te-doped epilayer. [ABSTRACT FROM AUTHOR]

Abstract: Erbium-doped hydrogenated amorphous silicon suboxide films containing silicon clusters (a-SiO x :H) were prepared. The samples exhibited photoluminescence (PL) peaks at around 750nm and 1.54μm, which could be assigned to the electron–hole recombination in silicon clusters and the intra-4f transition in Er3+, respectively. We compared annealing behaviors of Si clusters and Er3+ emission and found that Si clusters emission depends strongly upon crystallinity of Si clusters, whereas Er3+ emission is not sensitive to whether it is Si nanocrystals (nc-Si) or amorphous Si (a-Si) clusters. The erbium-doped a-SiO x :H films containing either a-Si clusters or nc-Si have the same kind of Er3+-emitting centers. Based on these results, it is concluded that a-Si clusters can play the same role on Er3+ excitation as nc-Si. [Copyright &y& Elsevier]

Zn1−xMnxSe thin films with different Mn compositions are grown by metal-organic chemical vapor deposition on GaAs substrate. Good crystallinity of sample is evidenced by X-ray diffraction and rocking-curve measurements. Photoluminescence (PL) properties were carefully studied. A dominant PL peak close to the band edge is observed at low temperature for samples with higher Mn concentration. The temperature-dependent PL and time-resolved photoluminescence show that this emission peak is associated with the recombination of exciton bound to Mn-induced impurity bound states. It is found that rapid thermal annealing can induce reorganization of Mn composition in alloys and significantly reduce the density of impurity induced by Mn incorporation and improve the intrinsic interband transition. [Copyright &y& Elsevier]