稀土(III)及铜(II)、锌(II)有机磷（膦）酸酯配合物的晶体结构和振动光谱研究

本文包括标题配合物的结构和振动光谱两部分，共涉及了M(DMP)_n {n=2.3, M=2a, Nd, Cu. Zn}, Ln(DPP)_3{2n=2a-2u, Y}和Ln(BBP)_3 {Ln=La-Lu. Y}三类三十四个配合物。在结构方面，首次测定了Zn(DMP)_2和Cu(DMP)_2呈现出链状配位高聚结构，而La(DMP)_3, La(DMP)_3则为平面网状配位高聚结构。在Zn(DMP)_2, La(DMP)_3和Nd(DMP)_3中，配体以对称“O－P－O”桥键与金属原子配位，在相邻金属原子间形成双桥键。在Zn(DMP)_2中，每个Zn原子通过“O－P－O”双桥键与另两个Zn原子连接，Zn原子配位数为4，配位多面体为四面体构型；在La(DMP)_3和Nd(DMP)_3中，每个稀土原子通过“O－P－O”双桥键与另外三个稀土原子相连接，稀土原子的配位数为6，配位多面体LnO_6为八面体构型。在Cu(DMP)_3中， 配体以对称和非对称“O－P－O”桥键两种形式存在，其中非对称配位的配体形成为“Cu-O-P_O-Cu"-Cu，在铜原之间形成了一个单氧桥键。每个Cu原子通过双“O－P－O”桥键以及双单氧原子桥键与另外三个Cu原子相连接，Cu原子配位数为5，配位多面体为四角锥构型。在振动光谱方面，得到了上述配合物较为完整的光谱数据，并对主要光谱带进行了归属，如V_(M-O), V_(PO_2), V_(P-O(c)),VC-O, VP-C及σ_PO_2等。在稀土配合物中，稀土配位键的伸缩振动V_(vn-o)位于250cm~(-1)附近。V_(Cu)和V_(Zn-o)，在Cu(DMP)_2和Zn(DMP)_2中，分别为(412cm~(-1), 370cm~(-1))和(393cm~(-1), 386cm~(-1))。V_(as)PO_2和V_sPO_2，在配合物振动光谱中，分别在1130－1249cm~(-1)区和1084－1156cm~(-1)区。在稀土配合物中，VL_(n-o), V_(as)PO_2频率值，随镧系收缩逐渐递增。在Cu(DMP)_2红外谱中，非对称配体和对称配体的V_(as)PO_2和V_sPO_2, 分别为(1249cm~(-1)，1156cm~(-1))及(1177cm~(-1)，1090cm~(-1))，其劈裂值△V(V_(as)PO_2-V_sPO_2)为93cm~(-1)和87cm~(-1)。通过对配合物的常温和低温红外光谱的比较，确认了La(DMP)3和Nd(DMP)_3的176cm~(-1)、Ln(DPP)_3和Ln(BBP)_3的150cm~(-1)附近吸收为晶格振动。Ln(DPP)_3、Ln(BBP_3)的光谱性质与Ln(DMP)_3相似，我们认为它们之间具有相同的骨架结构－平面网状配位高聚结构。

HEH（EHP）、H（DEHP）萃取铒（III）的动力学和机理的研究

萃取动力学的研究方法主要有：恒界面池法，充分混合法，单液滴法、生长液滴法，短时间相接触法和支撑液膜法。由于生长液滴法仪器简单，易于操作，且对于萃取速率快的体系尤为适宜，从而受到人们的注意。本文主要采用生长液滴法和充分混合法。本文分别研究了HEH（EHP）、H（DEHP）从盐酸介质中萃取E_r（III）的动力学和HEH（EHP）从硫酸介质中萃取E_rIII）的动力学，并讨论了萃取机理。实验表明，对于不同的萃取体系，其萃取机理不同。本论文做了以下几个方面的工作。1、HEH（EHP）从HCl介质中萃取E_r(III）的动力学和机理；2、HEH（EHP）从H_2SO_4介质中萃取E_r(III）的动力学和机理；3、H（DEHP）从HCl介质中萃取Er(III）的动力学。

铜（III）及相关化合物的合成和性质的研究，稀土复合氟化物电性、氧敏和氢敏性质

本论文包括两部分内容。第一部分为“Cu(III)及相关化合物的合成和性质的研究”；第二部分为“稀土复合氟化物的电性、氧敏和氢敏性质”。第一部分的主要内容有：1.制备了Na_4H[Cu(H_2TeO_6)_2]·17H_2O和Na_4K[Cu(HIO_6)_2]·12H_2O的Cu(III)单晶配合物。2.在比较相应的Cu(II)化合物的条件下，详细地研究了这二个Cu(III)配合物的电子光谱和Cu2p光电子能谱，由于价态升高，场强参数增大，Cu(III)化合物的d-d跃迁相对于Cu(II)化合物d-d跃迁，发生“蓝移”。3.成功地实现了用O_3和电化学方法对强碱溶液中Cu(II)配合物的氧化，获得了二个新的Cu(III)固态配合物Ba_4K[Cu(H_2TeO_6)_2] (OH)_4·6H_2O和Ba_3K[Cu(HIO_6)_2] (KOH)_(0.5)(OH)_2·8H_2O利用化学分析、磁学性质、电子光谱和Cu2p XPS，对这二个化合物进行了表征。4.对BaCuO_(2.5)的合成、电学性质、磁学性质、Cu(III) ESR和Cu2p XPS进行了研究。5.以Na_4K[Cu(HIO_6)_2]·12H_2O和BaCuO_(2.5)为参照物，用电子光谱和Cu2p XPS，确认了YBa_2Cu_3O_(7-5)中的高价态的铜。6.考察了以Cu（III）化合物作为Cu部分原料所合成的YBCO系超导材料的电学性质。第二部分的主要内容有：1.测试了元件“BiF_3(Bi)/Ce_(0.95)Ca_(0.05)F_(2.95)/Pt”的氧敏、氢敏等性能。从室温到130 ℃，元件的氧敏机理为“双电子反应”，电动势（EMF）与氧分压遵循Nernst关系式。室温时，元件对空气中100Pa或1000Pa氢气的响应时间仅为15秒或短于5秒；氢分压在16Pa～1000Pa范围内，EMF与氢分压的对数呈线性关系，斜率为-116mV/decade, 敏感机理表现为“混合电极电势”。元件具有良好的氢敏性能，并有一定的选择性。2.合成并测试了La_(1-x)Pb_xF_(3-x)(X = 0.00 ～ 0.15)的电导率，La_(0.95)Pb_(0.05)F_(2.95)的电导率最高，比LaF_3高约一个数量级。以La_(0.95)Pb_(0.05)F_(2.95)为固体电解质材料，Pd或Pt为敏感电极，BiF_3(Bi)或PbF_2(Pb)为参比电极，制成了四个元件。其中，“BiF_3(Bi)/La_(0.95)Pb_(0.05)F_(2.95)/Pt”具有最好的氧敏、氢敏性能。从室温到150 ℃，元件的EMF与1gPo_2附合Nernst关系式。150 ℃时，元件对氧气的响应时间仅为80秒。室温下，元件对空气中100Pa或1000Pa氢气的响应时间仅为75秒或15秒，元件的电动势EMF与氢分压的关系可表示为“E=E_o-96lgP_(H2)(mV)”。元件对CO有较差的敏感性能，而对空气中甲烷、乙烷或乙炔（≤1000Pa）不具敏感性能。3.合成并测试了Ln_(1-x)Pb_xF_(3-x)(Ln=Ce、Pr、Nd和Gd、Dy、Ho、Yb)的电性。前四个系列为离子导体材料，后三个系列可能为P型半导体。随着Ln原子序数增大，LnF_3导电性能变差；La~(3+)、Ce~(3+)、Pr~(3+)、Nd~(3+)与Pb~(2+)离子半径差异较小，LnF_3和PbF_2可以形成固溶体；而Gd~(3+)、Dy~(3+)、Ho~(3+)、Yb~(3+)与Pb~(2+)离子半径差异较大，LnF_3和PbF_2难以形成固溶体。

INTERVALLEY-GAMMA-CHI DEFORMATION POTENTIALS IN III-V ZINCBLENDE AND SI SEMICONDUCTORS BY AB-INITIO PSEUDOPOTENTIAL CALCULATIONS

Intervalley GAMMA - X deformation potential constants (IVDP's) have been calculated by first principle pseudopotential method for the III-V zincblende semiconductors AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs and InSb. As a prototype crystal we have also carried out calculations on Si. When comparing the calculated IVDP's of LA phonon for GaP, InP and InAs and LO phonon for AlAs, AlSb, GaAs, GaSb and InSb with a previous calculation by EPM in rigid approximation, good agreements are found. However, our ab initio pseudopotential results of LA phonon for AlAs, AlSb, GaAs, GaSb and InSb and LO phonon for GaP, InP and InAs are about one order of magnitude smaller than those obtained by EPM calculations, which indicate that the electron redistributions upon the phonon deformations may be important in affecting GAMMA - X intervalley shatterings for these phonon modes when the anions are being displaced. In our calculations the phonon modes of LA and LO at X point have been evaluated in frozen phonon approximation. We have obtained, at the same time, the LAX and LOX phonon frequencies for these materials from total energy calculations. The calculated phonon frequencies agree very well with experimental values for these semiconductors.

INTERVALLEY GAMMA-CHI DEFORMATION POTENTIALS IN III-V ZINCBLENDE SEMICONDUCTORS BY ABINITIO PSEUDOPOTENTIAL CALCULATIONS

Intervalley GAMMA-X deformation-potential constants (IVDP's) have been calculated by use of a first-principles pseudopotential method for the III-V zinc-blende semiconductors AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, and InSb. When the calculated IVDP's of LA phonons for GaP, InP, and InAs and of LO phonons for AlAs, AlSb, GaAs, GaSb, and InSb are compared with results of a previous calculation that used the empirical pseudopotential method (EPM) and a rigid-ion approximation, good agreement is found. However, our ab initio pseudopotential results on IVDP's of LA phonons for AlAs, AlSb, GaAs, GaSb, and InSb and of LO phonons for GaP, InP, and InAs are about one order of magnitude smaller than those obtained by use of EPM calculations, indicating that the electron redistribution accompanying crystal-lattice deformation has a significant effect on GAMMA-X intervalley scattering for these phonon modes when the anions are being displaced. In our calculations the LA- and LO-phonon modes at the X point have been evaluated in the frozen-phonon approximation. We have also obtained the LAX- and LOX-phonon frequencies for these materials from total-energy calculations, which agree very well with experimental values for these semiconductors. We have also calculated GAMMA-X hole-phonon scattering matrix elements for the top valence bands in these nine semiconductors, from which the GAMMA-X IVDP's of the top valence bands for the longitudinal phonons and transverse phonons are evaluated, respectively.

1ST PRINCIPLES PSEUDOPOTENTIAL CALCULATIONS OF ZONE BOUNDARY PHONON FREQUENCIES OF III-V-ZINCBLENDE SEMICONDUCTORS

Longitudinal zone boundary X phonon frequencies have been calculated by a first principles pseudopotential method for III-V zincblende semiconductors AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs and InSb. The phonon frequencies have been evaluated from total energy calculations in the frozen phonon approximation. The calculated phonon frequencies agree very well with the experimental values.

不同状态MnO2对废水中As（III）的吸附研究

于2010-11-23批量导入

High power continuous-wave operation of self-organized In(Ga)As/GaAs quantum dot lasers

Quantum dot (QD) lasers are expected to have superior properties over conventional quantum well lasers due to a delta-function like density of states resulting from three dimensional quantum confinements. QD lasers can only be realized till significant improvements in uniformity of QDs with free of defects and increasing QD density as well in recent years. In this paper, we first briefly give a review on the techniques for preparing QDs, and emphasis on strain induced self-organized quantum dot growth. Secondly, self-organized In(Ga)As/GaAs, InAlAs/GaAlAs and InAs/InAlAs Qds grown on both GaAs and InP substrates with different orientations by using MBE and the Stranski-Krastanow (SK) growth mode at our labs are presented. Under optimizing the growth conditions such as growth temperature, V/III ratio, the amount of InAs, InxGa1-xAs, InxAl1-xAs coverage, the composition x etc., controlling the thickness of the strained layers, for example, just slightly larger than the critical thickness and choosing the substrate orientation or patterned substrates as well, the sheet density of ODs can reach as high as 10(11) cm(-2), and the dot size distribution is controlled to be less than 10% (see Fig. 1). Those are very important to obtain the lower threshold current density (J(th)) of the QD Laser. How to improve the dot lateral ordering and the dot vertical alignment for realizing lasing from the ground states of the QDs and further reducing the Jth Of the QD lasers are also described in detail. Thirdly based on the optimization of the band engineering design for QD laser and the structure geometry and growth conditions of QDs, a 1W continuous-wave (cw) laser operation of a single composite sheet or vertically coupled In(Ga)As quantum dots in a GaAs matrix (see Fig. 2) and a larger than 10W semiconductor laser module consisted nineteen QD laser diodes are demonstrated. The lifetime of the QD laser with an emitting wavelength around 960nm and 0.613W cw operation at room temperature is over than 3000 hrs, at this point the output power was only reduced to 0.83db. This is the best result as we know at moment. Finally the future trends and perspectives of the QD laser are also discussed.

Characterization of GaSb substrate wafers for MOCVD III-V antimonides

The qualities of GaSb substrates commonly used for the preparation of III-V antimonide epilayers were studied before and after growing GaInAsSb multi-layers by MOCVD using PL, FTIR and DCXD together with the electrical properties and EPD value. The correlation between the substrate qualities and epilayer properties was briefly discussed. The good property epilayers of GaInAsSb and, then, the high preformance of 2.3 um photodetectors were achieved only using the good quality GaSb wafers as the substrates.