Sb complexes and Zn interstitials in Sb-implanted ZnO epitaxial films

In the present work, post-annealing is adopted to investigate the formation and the correlation of Sb complexes and Zn interstitials in Sb-ion implanted ZnO films, by using Raman scattering technique and electrical characterizations. The damage of Zn sublattice, produced by ion bombardment process is discerned from the unrecovered E2 (L) peak in annealed high Sb+ dose implanted samples. It is suggested that the Zn sublattice may be strongly affected by the introduction of Sb dopant because of the formation of SbZn-2VZn complex acceptor. The appearance of a new peak at 510 cm 1 in the annealed high dose Sb+ implanted samples is speculated to result from (Zn interstitials-O interstitials) Zni-Oi complex, which is in a good accordance with the electrical measurement. The p-type ZnO is difficult to obtain from the Sb+ implantation, however, which can be realized by in-situ Sb doping with proper growth conditions instead.     

Developing cold-resistant high-adhesive electronic substrate for WIMPs detectors at CDEX

Herein we report a prototypical electronic substrate specifically designed to serve the weakly interacting massive particles(WIMPs)detectors at the China Dark Matter Experiment(CDEX).Because the bulky high-purity germanium(HPGe)detectors operate under liquid-nitrogen temperatures and ultralow radiation backgrounds,the desired electronic substrates must maintain high adhesivity across different layers in such cold environment and be free from any radioactive nuclides.To conquer these challenges,for the first time,we employed polytetrafluoroethylene((C2F4)n)foil as the base substrate,in conjunction with ion implantation and deposition techniques using an independently developed device at Beijing Normal University for surface modification prior to electroplating.The remarkable peeling strengths of 0.88±0.06 N/mm for as-prepared sample and 0.75±0.05 N/mm for that after 2.5-days of soaking inside the liquid nitrogen were observed,while the regular standards commonly require 0.4 N/mm^0.6 N/mm for electronic substrates.     

Sine-Gordon方程的动态边界反馈镇定

考虑一端固定,控制输入在另一端的Sine-Gordon方程的动态边界反馈镇定问题.我们给出闭环系统的适定性,并利用乘子方法得到在动态边界反馈控制下闭环系统的多项式衰减率.     

First-principle study of Mg adsorption on Si（111） surfaces

We have carried out first-principle calculations of Mg adsorption on Si(111) surfaces. Different adsorption sites and coverage effects have been considered. We found that the threefold hollow adsorption is energy-favoured in each coverage considered, while for the clean Si(111) surface of metallic feature, we found that 0.25 and 0.5 ML Mg adsorption leads to a semiconducting surface. The results for the electronic behaviour suggest a polarized covalent bonding between the Mg adatom and Si(111) surface.     

非迭代冻结密度近似方法在计算氢键相互作用的合理性研究

为计算相互作用较弱的分子碎片之间的耦合能,Harris从密度泛函理论出发,提出了一种简化方法,即冻结密度近似(FDA)方法.对该方法在描述分子间氢键作用的合理性进行了验证.对水分子间的HO┉H氢键、甲酰胺与水分子间的NH┉O氢键、二氟甲烷和水分子间的OH┉F氢键,以及DNA中的碱基(AT,GC)之间的N—H┉O,N—H┉N等类型的氢键的计算表明:若电子交换关联采用非定域自旋密度近似,FDA的计算结果同其他abinitio方法的计算结果以及实验结果都符合得很好.FDA在计算过程中既不需要求解泊松方程,也不需要进行反复的自洽迭代,所以运算速度较快,在研究生物大分子体系中的氢键相互作用方面具有一定的使用价值 关键词： 冻结密度近似 氢键 密度泛函     

用拉曼光谱测量离子注入引起的晶格应变

 对于10个周期的AlAs/GaAs超晶格和25个周期的GaAs/Ga0.92In0.08As超晶格,在室温下进行0.28 MeV的Zn＋注入,注入剂量为5×10¹³~5×10¹⁴ cm^-2。通过拉曼光谱测量,定量地分析了由于离子注入所引起的晶格内应变。实验结果表明：在所选用的注入剂量下,由于离子注入引起的应变小于体材料GaAs的最大非驰豫应变值0.038,说明该注入条件下,注入区的结晶态仍然保持得比较好。在较高注入剂量下应变达到饱和,说明缺陷的产生和复合达到了平衡,从而形成了均衡的应变场分布。