Eu-zinc oxide (ZnO) has been fabricated on a p-diamond substrate by a hydrothermal technique. Efficient Eu-ZnO/diamond visible light emission is observed in the electroluminescence process. The mechanism for the energy transfer behavior and the emissions is discussed.Semiconductors doped with rare earth (RE) elements have attracted much attention in recent years due to their novel optical properties and promising applications in many elds, such as ber ampliers, light emitting devices and uorescent lamps. 1-4 In most of these applications, efficient energy transfer from the host to the RE 3+ is desired. ZnO with a band gap of 3.37 eV and a bound exciton energy of 60 meV is also an important semiconductor for which UV and visible emissions are widely reported. 5 Unfortunately, the work of harvesting intense Eu 3+ emission from ZnO lms, ceramics, and powders remains disappointing because of the strong quenching effect of the wide-band, self-activated, green or yellow emissions and the higher energy-level position of Eu 3+ relative to the bottom conduction band (CB). 6 It has been established that direct ZnO / Eu 3+ energy transfer seems physically impossible, as the radiative and nonradiative decay of excitons in ZnO are >10 2 times faster than the energy-transfer rate of RE 3+ . Fortunately, energy transfer can be facilitated by the presence of intrinsic or extrinsic defects as energy trap centers in various systems, such as ZnO/diamond, 7 which suggests that the introduction of an appropriate trap center is crucial for efficient ZnO / Eu 3+ energy transfer. Several groups have reported that defects, either intrinsic or extrinsic, can serve as the energy trapping centers to facilitate energy transfer and relevant light emission. Park et al. indicated that extrinsic defects like chlorine impurities can assist the red emission in Eu 3+ -doped ZnO. 8 Wang et al. reported the surface defects may act to help the process of energy transfer from ZnO to Eu 3+ ions. 9 Zeng et al. indicated that in Eu-doped ZnO microspheres Eu 2+ ions act as the trapping centers and transfer energy to Eu 3+ ions, leading to the emission. 10In this work, nanostructural Eu doped n-ZnO on p-type diamond has been fabricated to research the current-voltage (I-V), electroluminescence (EL) and photoluminescence (PL) properties. For the rst time, efficient Eu-ZnO/diamond visible light emission was observed. The Eu-ZnO/diamond has been realized with good rectifying behavior. By rst-principles calculation, it is demonstrated that the doped Eu atoms are favorable to the octahedral interstice in ZnO lattice.The polycrystalline diamond lm is deposited on Si wafer by hot lament CVD system. 11 Boron source of diborane or trimethylborate was additionally introduced to the reaction gases of methane/hydrogen (CH 4 /H 2 ). Before the hydrothermal process, a ZnO seed layer was deposited by radio frequency (at 13.56 MHz) magnetron sputtering process. For the hydrothermal growth, the aqueous solution of zinc acetate dihydrate and hexamethylenetetramine ...
In situ microlevel spherical B2 CuZr phase reinforced Zr 49.5 Cu 36.45 Ni 4.05 Al 9 Nb 1 bulk metallic glass matrix composite was prepared successfully by the copper mold casting method. It was found that mechanical properties of Zr 50.5 Cu 36.45 Ni 4.05 Al 9 alloy were improved largely due to the Nb addition. The room-temperature compressive fracture strength and plastic strain for Zr 49.5 Cu 36.45 Ni 4.05 Al 9 Nb 1 rod with a diameter of 5 mm reaches 2037 MPa and 8%, respectively. The improvements are attributed to the precipitation of the spherical B2 CuZr phase distributed uniformly in amorphous matrix, which effectively hampers the propagation of shear bands by deflecting them at the interface and by a multiplication mechanism.
We report on the custom produced low radiation background stainless steel and the welding rod for the PandaX experiment, one of the deep underground experiments to search for dark matter and neutrinoless double beta decay using xenon. The anthropogenic 60 Co concentration in these samples is at the range of 1 mBq/kg or lower. We also discuss the radioactivity of nuclear-grade stainless steel from TISCO which has a similar background rate. The PandaX-II pressure vessel was thus fabricated using the stainless steel from CISRI and TISCO. Based on the analysis of the radioactivity data, we also made discussions on potential candidate for low background metal materials for future pressure vessel development.
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