Dual codoping for the fabrication of low resistive p-ZnO

A dual codoping method has been proposed to fabricate low resistive and stable p-ZnO thin films. Both nitrogen (N) and arsenic (As) have been used as acceptors while aluminum (Al) as donor in our dual codoping process. The As-Al-N dual codoped ZnO films have been prepared by RF magnetron sputtering on GaAs substrate using AlN doped ZnO targets (0.5, 1 and 2 mol%). In our dual codoping approach, Al and N from target and As from GaAs substrate (back diffusion) take part. X-ray diffraction (XRD), room temperature and low temperature photoluminescence (PL), electron probe micro analysis (EPMA), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and Hall effect measurement have been performed to investigate the effect of AlN concentration on the dual codoped ZnO films. All the films (0, 0.5 and 1 mol%) showed p-type conductivity except 2 mol% AlN doped film. The lowest room temperature resistivity, 8.6 × 10⁻² Ω cm has been achieved with a hole concentration of the order, 10²⁰ cm⁻³ for the optimum 1 mol% AlN concentration. The observed resistivity is much lower than that of monodoped (As or N) and codoped (AlN or AlAs) ZnO films. The p-type conductivity has been explained by the new complex formation mechanism.     

3D Sulfur and Nitrogen Codoped Carbon Nanofiber Aerogels with Optimized Electronic Structure and Enlarged Interlayer Spacing Boost Potassium‐Ion Storage

Carbonaceous materials are promising anodes for potassium‐ion batteries (PIBs). However, it is hard for large K ions (1.38 Å) to achieve long‐distance diffusion in pristine carbonaceous materials. In this work, the following are synthesized: S/N codoped carbon nanofiber aerogels (S/N‐CNFAs) with optimized electronic structure by S/N codoping, enhanced interlayer spacing by S doping, and a 3D interconnected porous structure of aerogel, through a pyrolysis sustainable seaweed (Fe‐alginate) aerogel strategy. Specifically, the S/N‐CNFAs electrode delivers high reversible capacities of 356 and 112 mA h g^?1 at 100 and 5000 mA g^?1, respectively. The capacity reaches 168 mA h g^?1 at 2000 mA g^?1 after 1000 cycles. A full cell with a S/N‐CNFAs anode and potassium prussian blue cathode displays a specific capacity of 198 mA h g^?1 at 200 mA g^?1. Density functional theory calculations indicate that S/N codoping is beneficial to synergistically improve K ions storage of S/N‐CNFAs by enhancing the adsorption of K ions and reducing the diffusion barrier of K ions. This work offers a facile heteroatom doping paradigm for designing new carbonaceous anodes for high‐performance PIBs.     

氮-铟共掺杂ZnO薄膜的制备及表征

以醋酸锌水溶液为前驱体,分别以醋酸铵和硝酸铟为氮(N)源和铟(In)源,采用超声喷雾热解法在石英玻璃衬底上沉积了氮铟(NIn)共掺杂ZnO薄膜。采用X射线衍射、场发射扫描电镜、霍尔效应、塞贝克效应、光致发光谱等分析方法,研究了NIn共掺杂对所得ZnO薄膜的晶体结构、电学和光学性能的影响规律。结果表明:通过氮铟共掺杂,ZnO薄膜的电学和光学性能发生明显改变。优化工艺条件下,所得ZnO基薄膜结构均匀致密,电阻率为6.75×103Ω·cm,并且在室温光致发光谱中检测到很强的近带边紫外发光峰,表明薄膜具有较理想的化学计量比和较高的光学质量。     

氧化锌p型共掺杂精细结构的第一性原理研究

计算了ZnO材料p型掺杂精细结构,分析了p型掺杂ZnO晶体的电子结构、电荷布局、电子态密度、差分电荷。所有计算都是基于密度泛函理论(DFT)框架下的第一原理平面波超软赝势方法。计算结果表明:掺杂Ⅴ族元素(N、P、As、In)的氧化锌材料在能隙中引入了深受主能级,载流子(空穴)局域于价带顶附近。而利用加入激活施主的共掺杂技术的计算结果却表明,受主能级向低能方向移动,形成了浅受主能级。同时,受主能级带变宽,非局域化特征明显。     

Effects of V and Zn codoping on the microstructures and photocatalytic activities of nanocrystalline TiO2 films

To enhance the photocatalytic activity of TiO₂, V and Zn co-doped TiO₂ films were synthesized by the sol–gel method. The experimental results indicated that the films were composed of round-like nano-particles or aggregates. V and Zn codoping could not only obviously increase the specific surface area of TiO₂ but also result in the narrowed band gap of TiO₂ sample. The photocatalytic activities of the TiO₂ films were evaluated by the photocatalytic decomposition of organic dyes in aqueous solution. Compared with un-doped TiO₂ film or single doped TiO₂ film, V and Zn co-doped TiO₂ film exhibited excellent photocatalytic activities under both UV light and visible light. The improvement mechanism by V and Zn codoping was also discussed.     

In含量变化对N-In共掺杂ZnO薄膜的结构和性能的影响

采用超声雾化热解法制备ZnO薄膜，对比分析了不同In含量的N-In共掺杂ZnO薄膜的显微结构，电学和光学性质。实验结果表明在N-In共掺杂条件下In的含量对ZnO薄膜的显微结构及性能有明显的影响。In的掺入使得ZnO中总体缺陷减少，晶粒外形更规则，C轴取向性更好。引入In能使ZnO更容易向P型转变；当前驱体溶液中In的比例〉0．03后，可以显著改善ZnO薄膜的电学性能和光学性能。     

First-principles calculations of electronic structure and optical properties of boron–phosphorus co-doped zinc oxide

This paper presents the electronic structure and optical properties of boron–phosphorus co-doped zinc oxide ((B, P) codoped ZnO) systems employing first principles calculations based on density functional theory. In the (B, P) codoped ZnO systems, dopants prefer to be located on the nearest-neighbor sites in the same (00l) plane forming B_Zn–P_O complex with binding energy of −1.92 eV; some hole sates appear above the valence band maximum. With increase in P concentration, P 3p states become more and more delocalized. The calculated optical properties indicate that strong optical transitions in lower energy region occur; the intensities and positions of these peaks are P concentration-dependent, which could be ascribed to the electronic transitions between P 3p and Zn 4s states. Moreover, the absorption coefficients and other optical constants of the (B, P) codoped ZnO systems, such as reflectivity, refractive index, and loss function, are also discussed.     

Broadband near-infrared emission in Er-Tm co-doped bismuthate glasses

In this work, we report near infrared emission spectra of Er³⁺-Tm³⁺ co-doped Bi₂O₃-GeO₂-Na₂O (BGN) glasses with the excitation of 800 nm laser. A broad emission extending from 1300 to 1650 nm with a full width at half maximum (FWHM) of ∼160 nm is obtained in a 1.0 wt% Tm₂O₃ and 0.3 wt% Er₂O₃ co-doped BGN glass. The energy transfer processes between Tm³⁺ and Er³⁺ in BGN glasses are analyzed in detail. The temperature dependence of the broadband emission spectra in Er³⁺-Tm³⁺ co-doped BGN glass is also studied. The present work indicates that Er³⁺-Tm³⁺ co-doped BGN glasses can be promising materials for broadband light sources and broadband amplifiers for WDM transmission systems.     

Zn-Zr共掺对0.95MgTiO_3-0.05CaTiO_3陶瓷介电性能的影响

采用固相反应法制备了(Mg0.93Ca0.05Zn0.02)(Ti1-xZrx)O3介质陶瓷。研究了Zn-Zr共掺杂对0.95MgTiO3-0.05CaTiO3(95MCT)陶瓷介电性能的影响。结果表明:Zn-Zr共掺杂能有效降低95MCT陶瓷的烧结温度至1 300℃,改善介电性能,并对介电常数温度系数αc具有调节作用。当Zn2+和Zr4+掺杂量均为摩尔分数0.02时,在1 300℃烧结2.5 h获得的95MCT陶瓷具有最佳介电性能:εr=22.02,tanδ=2.78×10-4,αc=2.98×10-6/℃。     

硼氮共掺杂TiO2粉末制备及光催化活性研究

采用溶胶-凝胶法制备硼氮共掺杂TiO₂光催化剂,利用X射线衍射、X射线光电子能谱及紫外-可见光漫反射光谱手段对制备的催化剂进行表征。结果表明,硼和氮均以间隙方式进入TiO₂晶格中,形成Ti-O-B、Ti-O-N和Ti-O-B-N结构,提高了催化剂活性;B-N-TiO₂吸收带边明显红移,表明催化剂对可见光吸收增强。可见光降解甲基橙结果表明,B-N-TiO₂的活性明显高于B-TiO₂和N-TiO₂,说明硼氮共掺杂改性对提高TiO₂可见光活性具有协同作用。