Zhe Kong

Preparation and Optimization of Long Persistent Luminescent Sr 4 Al 14 O 25 :(Eu,Dy) Phosphor Materials: Preparation and Optimization of Long Persistent Luminescent Sr 4 Al 14 O 25 :(Eu,Dy) Phosphor Materials

本文利用固相反应法制备了Sr 4 Al 14 O 25 :(Eu 2+ , Dy 3+ )长余辉夜光材料, 并研究了H 3 BO 3 含量、固相反应温度和Eu含量对Sr 4 Al 14 O 25 :(Eu 2+ , Dy 3+ )长余辉夜光材料性能的影响. 实验结果表明, H 3 BO 3 含量对蓝绿发射的Sr 4 Al 14 O 25 相的形成至关重要. 在固相反应温度为1400℃, H 3 BO 3 含量为10at%, Eu/Al原子比为0.03的优化条件下, 获得了发射波长为490 nm, 余辉时间长达24 h以上的Sr 4 Al 14 O 25 夜光粉. 发光强度与Eu含量的关系证明, Sr 4 Al 14 O 25 相的蓝绿发射过程主要受电子从深陷阱到Eu 2+ 能级的转移速度的控制.本文利用固相反应法制备了Sr 4 Al 14 O 25 :(Eu 2+ , Dy 3+ )长余辉夜光材料, 并研究了H 3 BO 3 含量、固相反应温度和Eu含量对Sr 4 Al 14 O 25 :(Eu 2+ , Dy 3+ )长余辉夜光材料性能的影响. 实验结果表明, H 3 BO 3 含量对蓝绿发射的Sr 4 Al 14 O 25 相的形成至关重要. 在固相反应温度为1400℃, H 3 BO 3 含量为10at%, Eu/Al原子比为0.03的优化条件下, 获得了发射波长为490 nm, 余辉时间长达24 h以上的Sr 4 Al 14 O 25 夜光粉. 发光强度与Eu含量的关系证明, Sr 4 Al 14 O 25 相的蓝绿发射过程主要受电子从深陷阱到Eu 2+ 能级的转移速度的控制.

Depth profiling of Al diffusion in silicon wafers by laser-induced breakdown spectroscopy

Al diffusion in silicon wafers at different temperatures was detected by laser induced breakdown spectroscopy (LIBS) in this work. An Al thin film with a thickness of about 800 nm was deposited on silicon wafers by magnetron sputtering and then post-annealed in air at 300 and 610 °C (or without post-annealing) to achieve different depth profiles. The depth profile of Al in the wafers was measured using energy dispersive spectroscopy (EDS) and LIBS. EDS almost can not distinguish between the different Al concentrations at deeper positions of the different samples due to its low detection limit. The LIBS experiment was performed in an atmospheric environment. The pulse fluence was fixed at 16 J cm−2 to cause an average ablation rate of 200 nm per pulse. LIBS can distinguish between the depth profiles of different diffusion samples very well. The results confirm that LIBS is very well suited for the detection of metal diffusion in silicon wafers.

Fabrication and Characterization of Transparent ZnO Film Based Resistive Switching Devices

In this paper, ZnO thin films were prepared on ITO conductive glass by direct current magnetron sputtering and the Cu electrodes were evaporated on ZnO/ITO by electric beam evaporation to get transparent Cu/ZnO/ITO resistive random access memory. The crystal structure and surface morphology were investigated by X-ray diffraction and atomic force microscopy, respectively. The transmittance spectra of ZnO/ITO in the visible region were measured by UV-VIS spectroscopy. The resistive switching characteristics of the fabricated devices were investigated by the voltage sweeping method, which showed that the transparent Cu/ZnO/ITO device had good resistive switching characteristics.

Effects of boric acid on structural and luminescent properties of BaAl2O4:(Eu2+, Dy3+) phosphors

Eu2+/Dy3+-codoped BaAl2O4 phosphors were prepared by conventional solid-state reaction with boric acid flux. The effects of boric acid on structural and luminescent properties of BaAl2O4:(Eu2+, Dy3+) were investigated. The crystallinity of BaAl2O4 improved with increasing amount of H3BO3. Incorporation of Eu2+ and Dy3+ ions into effective lattice sites was promoted by H3BO3 addition. As a result, Eu2+ emission in BaAl2O4 was greatly enhanced by H3BO3, and the duration of persistent luminescence increased with the amount of H3BO3. However, the decay lifetime of persistent luminescence was not strongly influenced by the amount of H3BO3.

Study on Preparation and Resistive Switching Characteristics of SnO2 Films

In this paper, resistance switching devices with Au/SnO2/Al sandwich structure were fabricated. The prepared devices showed a reliable unipolar resistance switching characteristic. The forming voltage of SnO2-based resistance devices increased with increasing film thicknesses, while SnO2 film thickness had little influence on set and reset voltages. When the SnO2 film thickness was 46 nm, the device showed steady and reliable conversion under voltage sweeping and the ratio between high and low resistance states was higher than 102, which can basically satisfy the requirements for practical application.