电极材料对碘化汞（α-HgI2）晶体I-V特性的影响

利用Aligent4155型CVIV测试仪分别对Au／HgI2、AuCl3（Au）／HgI2、C（石墨）／HgI2接触的I-V特性进行了测定,对比研究了不同电极材料与α—HgI2晶体所形成的接触特性,并利用热电子发射理论对实验结果进行了分析。结果表明,AuCl3和C均能与HgI2形成良好的欧姆接触,其欧姆特性系数分别为1．0291和0．9380,接触电阻分别为3．0×10^8Ω和1．0×10^8Ω;而溅射Au与HgI2接触的欧姆特性较差,欧姆系数约为0．8341,接触电阻为3．5×10^9Ω。这说明AuCl3在HgI2表面形成了重掺杂,产生显著的隧道电流,从而形成了较理想的欧姆接触。C（石墨）化学性能稳定,电极制备工艺没有影响晶体表面质量,因此C（石墨）／HgI2接触电阻最小,并具有良好的欧姆特性。而溅射Au过程中由于温度升高引起晶体表面HgI2分子的挥发,造成晶体表面质量下降,导致Au／HgI2接触的欧姆特性变差。     

HgI2晶体最低生长温度的确定

为确定HgI2晶体的最佳生长温度,根据邻位面生长的台阶动力学,推导出HgI2分子在(001)面扩散激活能ESD约为0.33 eV,进而采用物理气相沉积法的基本理论推算了不同升华温度T1下HgI2晶体生长的最低温度Tmin.结果表明,计算结果与实际晶体生长温度基本一致.该结果为HgI2单晶体、多晶薄膜、单晶薄膜沉积工艺的优化提供了依据.     

结构缺陷对HgI2晶体光吸收的影响

为研究HgI2晶体结构缺陷与光吸收的关系,测试了晶体的UV和中红外透过光谱.结果表明,波长约为580 nm时,存在着本征吸收限;波长大于580 nm时,随波长增加,晶体对光的吸收减小,透过率达到45;以上;在1000～2500 nm范围内,UV光谱存在四个明显的光吸收带,对应的入射光能量分别为0.79±0.01 eV,0.72 eV,0.57±0.01 eV 和0.53 eV.中红外透过曲线随波长增加而增大,透过率为39;～68;.通过M/HgI2的I～t曲线,采用简单能级模型进一步确认了生长的HgI2晶体存在0.79±0.01 eV和0.72 eV两个陷阱能级.分析认为,HgI2晶体层间的相对移动形成的结构缺陷造成1572.5 nm(0.79±0.01 eV)和1729.2 nm(0.72 eV)处的吸收,晶体缺碘造成2117.5 nm(0.57±0.01 eV)处的吸收和汞空位造成2305.8 nm(0.53 eV)的吸收.在中红外波段,晶体结构缺陷造成了显著的晶格吸收.严格控制原料的化学计量比有利于减少HgI2晶体的结构缺陷,提高晶体的光学性能.     

电极材料对碘化汞(α-HgI2)晶体Ⅰ-Ⅴ特性的影响

利用Aligent4155型CVIV测试仪分别对Au/HgI2、AuCl3(Au)/HgI2、C(石墨)/HgI2接触的,Ⅰ-Ⅴ特性进行了测定,对比研究了不同电极材料与α-HgI2晶体所形成的接触特性,并利用热电子发射理论对实验结果进行了分析.结果表明,AuCl3和C均能与HgI2形成良好的欧姆接触,其欧姆特性系数分别为1.0291和0.9380,接触电阻分别为3.0×108Ω和1.0×108Ω;而溅射Au与Hg2接触的欧姆特性较差,欧姆系数约为0.8341,接触电阻为3.5×109Ω.这说明AuCl3,在HgI2表面形成了重掺杂,产生显著的隧道电流,从而形成了较理想的欧姆接触.C(石墨)化学性能稳定,电极制备工艺没有影响晶体表面质量,因此C(石墨)/HgI2接触电阻最小,并具有良好的欧姆特性.而溅射Au过程中由于温度升高引起晶体表面HgI2分子的挥发,造成晶体表面质量下降,导致Au/HgI2接触的欧姆特性变差.     

Au/p-CZT晶体的光致发光以及电学性能研究

对比了CZT晶片经腐蚀与钝化表面处理的PL谱,结果表明NH4F/H2O2作为CZT晶体表面钝化剂,钝化后CZT晶体表面陷阱态密度减小到最低程度,同时减小了与Cd空位复合有关的深能级杂质浓度。用Agilent 4339B高阻仪进行CZT晶片I-V特性测试以及Agilent 4294A高精度阻抗分析仪进行CZT晶片的C-V特性测试,结果表明钝化均能不同程度提高Au/p-CZT接触的势垒高度,减小了漏电流。主要原因是在CZT表面钝化生成的TeO2氧化层增加接触势垒高度,并减小了电荷因隧道效应而穿过氧化层的几率。     

Ti/Au复合电极在CdZnTe(111)B面上的表面结构与性能研究

近年来,碲锌镉(CdZnTe)材料制成的探测器已经成为研究热点,适当的接触特性已经成为提高探测器性能的关键问题。本文主要探讨了弱n型CdZnTe晶体(111)B面Ti/Au复合电极的欧姆接触性能,采用两步沉积工艺制备Ti/Au复合电极。通过AFM、FIB/TEM、XPS、I-V等测试方法研究了电极与CdZnTe的界面结构、化学成分和电学性能。结果表明,Ti过渡层的引入可以减轻和改善晶片抛光过程中形成的损伤层,增加了电极与晶体之间的欧姆特性。相比于CdZnTe (111)B面上的Cr/Au复合电极,Ti/Au复合电极的粗糙度更低、接触界面更平整,晶格失配层厚度也更低。Ti中间层促进了金/半界面的互扩散现象, 有利于增加黏附性和降低肖特基势垒,并且在Ti/Au复合电极与CdZnTe接触的界面上没有观察到氧元素的存在。I-V测试表明Ti/Au复合电极具有更加良好的欧姆特性和更低的肖特基势垒。     

碘化汞(α-HgI2)晶体生长及其性能表征

利用垂直两温区透明油浴炉,采用升华法成功生长了α-HgI2单晶体.通过对比不同生长阶段晶体生长界面,观察到HgI2晶体在气相生长中存在界面形貌转变.晶体生长初期的生长面呈棱面,然后逐渐转变为圆滑界面.利用XRD、透射光谱以及I-V测试对所生长晶体的性能进行了表征.XRD结果表明所生长的晶体为单相的α-HgI2晶体,晶体的生长方向为[001].紫外-可见-近红外透过光谱分析发现,HgI2晶体的截至波长为580 nm,对应的禁带宽度为2.12 eV,近红外区内透过率约为45;.由于空穴的俘获及陷阱能级作用,在2307.5 nm和1731.4 nm处产生了两个明显的吸收峰.所生长的α-HgI2晶体电阻率约为1011Ω·cm,满足制作核辐射探测器的要求.     

基于暗I-V特性曲线对晶硅电池杂质和缺陷性质研究

暗I-V特性曲线是一种有效监测晶硅电池内部杂质和缺陷性质的表征手段.本文利用有限差分法较系统地研究了杂质和缺陷性质对暗I-V特性曲线的影响,并给出了利用暗I-V特性曲线判断晶硅电池内部杂质和缺陷类型和分布的基本准则,结果表明:在大于0.75 V的正向偏压区域,暗I-V特性曲线的明显变化可作为判断为由晶硅电池体内杂质和缺陷引起;在0.1 V~0.75 V的正向偏压区域,暗I-V特性曲线的理想因子分区性质可作为晶硅电池体内和表面杂质和缺陷的依据.     

ZnO过渡层对Au/Hg3In2Te6肖特基接触特性的影响研究

利用脉冲激光沉积技术在Hg3In2Te6晶体表面制备ZnO过渡层,并对ZnO过渡层进行了表征.结合X射线光电子能谱深度剖析对ZnO/Hg3In2Te6界面元素的化合态进行研究,并通过半导体参数分析仪对Au/ZnO/Hg3In2Te6肖特基接触电学特性进行测试.研究结果表明,采用本实验条件可在Hg3In2Te6晶体表面获得结晶度高、表面粗糙度低,且沿(002)晶面择优生长的ZnO过渡层.同时,ZnO过渡层的引入使Au/Hg3In2Te6肖特基接触的漏电流降低一个数量级,势垒高度提高6.5;.这种现象可能是由于ZnO/Hg3In2Te6界面存在的互扩散使O原子占据了Hg原子空位,从而降低耗尽层中能级缺陷而引起.     

透明导电薄膜与p-Si:H膜接触特性的研究

本实验采用PECVD方法在不同透明导电薄膜上沉积了p型掺杂(p-Si:H)膜.用拉曼(Raman)光谱测试了p-Si:H膜的晶化率,并用扫描电子显微镜(SEM)观察了其形貌.结果表明:在SnO2上沉积的p-Si:H膜的晶化率较其它两种衬底高,相应的SEM形貌显示颗粒尺寸也较大.通过I-V测试仪测试了ZnO:Al/p-Si:H、SnO2/p-Si:H和SnO2/ZnO:Al/p-Si:H的接触特性,结果显示ZnO:Al/p-Si:H的接触特性并不比SnO2/p-Si:H差.     

Ca3NbGa3Si2O14晶体的BAW传播特性

本文计算了沿Ca3NbGa3Si2O14(CNGS)晶体的x、y和z方向传播的声体波(BAW)的声速,绘制了yz、xy和xz面传播的慢速度分布曲线.这些结果对CNGS晶体在压电器件的设计、开发及利用方面具有一定的理论指导意义.     

Nd3+:LiLa(MoO4)2晶体生长、光谱和激光特性

本论文报道了Nd3+:LiLa(MoO4)2晶体生长、光谱和激光特性.采用提拉法生长出尺寸为φ20×34mm3的Nd+3+:LiLa(MoO4)2晶体.应用Judd-Ofelt理论计算了Nd3+离子在Nd3+:LiLa(MoO4)2晶体中唯象强度、自发发射跃迁几率、荧光分支比、辐射跃迁寿命和荧光量子效率.Nd3+:LiLa(MoO4)2晶体的偏振吸收跃迁截面分别为9.52×10-20cm2(π-偏振)和4.46×10-20cm2(σ-偏振).它的偏振发射跃迁截面分别为0.67×10-19cm2(σ-偏振)和1.02×10-19cm2(σ-偏振).在氙灯泵浦下,获得74.4mJ的1.06μm的激光输出,激光阈值为0.676J,激光总效率和斜率效率分别为0.39;和0.48;.     

Spectroscopic study of phosphine selenide complexes of Au(I) and X-ray structure of [(cyclohexyl)3PSeAuBr]

The X-ray structure determination of the complex, [(cyclohexyl)₃PSe-AuBr], revealed a triclinic space group P-1, with a = 9.7654(7), b = 10.9441(9), c = 11.2064(9) Å, = 117.076(6)°, = 99.076(6)° = 95.417(6)°, V = 1034.07(14) ų and Z = 2. The Au(I) atom in this complex has a linear coordination with Se1 atom at 2.3776(9) Å on one side and Br1 at 2.3843(9) Å at the trans position making the Se1-Au1-Br1 angle of 177.97(4)°. The P1 atom in the phosphine has tetrahedral geometry. All three cyclohexyl groups are in their usual boat conformation. The phosphorus atom of the triphenylphosphine is approximately perpendicular to the Se1—Au1—Br1 linkage with P1—Se1—Au1 angle of 99.19(6)°. The in the ³¹P NMR of the free ligands and their corresponding L—Se—Au—Br (L—Se = trialkyl/arylphosphine selenides) complexes, and the changes in the P—Se bond frequencies in the FTIR upon complexation, are indicative of the bonding of the ligand to Au(I) through selenium. There is a strong corelation between the chemical shifts of the ³¹P NMR and the C—P—C angle in the phosphines.     

Crystal and molecular structures of tri(o-tolyl)phosphinegold(I) purine-6-thiolate ethanol solvate (1/1) and tri(c-hexyl)phosphinegold(I) 6-methyl-2-thiouracilate

The crystal and molecular structures of the title compounds, [(o-tol)₃PAu(6-MP)]·EtOH and [(c-hexyl)₃PAu(6-Me-2-TU)], have been determined and each show the presence of a linear geometry about the Au atom; both of the thionucleobases function as thiolate ligands. Important interatomic parameters for [(o-tol)₃PAu(6-MP)] are Au–S 2.266(2), Au–P 2.239(2) and S–Au–P 177.03(8)° and for [(c-hexyl)₃PAu(6-Me-2-TU)]: Au–S 2.299(3), Au–P 2.244(3) and S–Au–P 176.1(1)°. Crystals of [(o-tol)₃PAu(6-MP)]·EtOH are monoclinic with space groupP2₁/n, and unit cell dimensionsa=10.067(2),b=10.518(2),c=25.416(4) , =98.42(2)°,Z=4. The structure was refined to finalR=0.040 for 4183 data withI3.0(I). Crystals of [(c-hexyl)₃PAu(6-Me-2-TU)] are monoclinic with space groupP2₁/c, and unit cell dimensionsa=9.692(4),b=15.822(4),c=15.775(3) , =94.00(2)°,Z=4,R=0.033 for 2666 data.     

Crystal structures of 3-methyl-1,2,4-benzotriazine 1-oxide and 2-oxide

The compound 3-methyl 1,2,4-benzotriazine 1,4-dioxide (1) belongs to a new class of clinically promising, bioreductively-activated antitumor drugs. Reductive metabolism of these triazine di-N-oxides typically produces mixtures of mono-N-oxide analogues. As part of our efforts toward characterization of the in vitro metabolism of 1, we synthesized the 1-oxide (2) and 2-oxide (3) analogues and characterized these compounds using X-ray crystallography. Compounds 2 and 3 (C₈H₇N₃O) crystallized in the monoclinic space group P2₁/c. Unit cell parameters for 2: a = 9.0466(7), b = 10.5959(8), c = 7.8981(6) ?, β = 98.4940(10), and z = 4. Unit cell parameters for 3: a = 5.7193(4), b = 9.3774(7), c = 13.8427(11) ?, β = 101.6370(10), and z = 4.Supplementary material X-ray crystallographic data reported in this paper is deposited with the Cambridge Crystallographic Data Center as supplementary publication numbers CCDC 294738 (compound 2) and CCDC 294739 (compound 3). Copies of available material can be obtained, free of charge, on application to the Director, CCDC, 12 Union Road, Cambridge CB21EZ, UK.     

绿柱石晶体的水热法生长及特征研究

采用温差水热法,以分析纯的Al(OH)3和BeO以及无色纯净的石英为原材料,球形和//s(1121)的片状无色绿柱石为籽晶,在复杂的盐酸混合溶液中生长了无色透明的绿柱石晶体.利用双圈反射测角仪、电子探针、X射线衍射仪和红外光谱仪等仪器,对合成绿柱石晶体的形态、成分及晶体结构进行了详细的研究.结果表明,合成的绿柱石晶体为六方短柱状,主要发育平行双面c{0001}、六方柱m{1010}、a{1120}和六方双锥p{1011}四种单形.合成的绿柱石晶体的成分中(Na2O+ K2O)的质量分数约为0.59;,且c0/a0值为0.9988,可归属于正常绿柱石向四面体绿柱石的过渡范畴.在中性或弱碱性环境体系中,通过调整绿柱石中各成分的百分含量,有望在更低的温度、压力条件下合成出高质量的板柱状绿柱石晶体.     

Na3La2(BO3)3晶体生长及光谱特性

本文以起始摩尔比为1:1的Na2CO3:H3BO3,并添加5;质量分数的NaF为助熔剂,用顶部籽晶法生长出φ35mm×5mm的透明Na3La2(BO3)3单晶.该晶体属正交晶系,空间群:Amm2,晶胞参数为a=0.51580(10)nm,b=1.1350(2)nm,c=0.73230(15)nm,α=β=γ=90°.测量了Na3La2(BO3)3晶体在室温下的透过光谱,紫外截止波长约为200nm.该晶体常温下稳定,不吸潮,但却易溶于稀酸.     

Crystal growth and characterization of Au3+ ion irradiated 2-amino-5-nitropyridinium hydrogen oxalate (2A5NPHO)

2-amino-5-nitropyridinium hydrogen oxalate (2A5NPHO) was grown using slow evaporation and bulk crystal of 2A5NPHO was harvested from Assembled Temperature Reduction (ATR) method. Cut and polished crystal was irradiated using Au³⁺ ion with various fluences. Electronic loss, nuclear energy loss and penetration depth were calculated using SRIM software. It was observed in X- ray pattern that intensity of peak was reduced. Intensity of peak decreased with increase of ion fluencies from 10¹³ ions/cm² to 10¹⁴ ions/cm². Optical properties were measured using UV-Vis spectrometer. The increase of absorption was due to excited electrons which were formed by vacancies and formation of additional defects centres. Energy band gap of irradiated crystals increased with increase of ion fluence. Energy band gap of irradiated crystals were 3.39 eV, 3.42 eV, and 3.4 eV for 10¹³ ions/cm², 5 × 10¹³ ions/cm² and 10¹⁴ ions/cm² respectively and increase of band gap was due to the increase of forbidden gap. Microhardness was calculated using Vicker's Hardness tester. Increase of microhardness in irradiation crystal was due to increase of high density lattice defects produced by Au³⁺ of 10.8 MeV. Electrical property was calculated using dielectric constant. Increase of dielectric constant was due to large polarization which caused by disorderness and rich defects in the crystalline surface. Decrease of intensity peak in fluorescence was due to transition of excited electron to intermediated energy levels from excited state which converted into vibrational energy of lattice atoms (phonon). Morphology of irradiated crystal was seen using scanning electron microscope (SEM). It was observed from the SEM image that surface of crystal was heavily damaged. It was also noticed that the thermal stability of the irradiated single crystal increased with increase of ion fluences. Impedance of irradiated crystal was measured. The bulk resistance and grain boundary resistance also were calculated.     

La2O3掺杂对BaTiO3-Nb2O5-Fe2O3陶瓷的晶体结构和介电性能的影响

研究了La2O3 掺杂对BaTiO3-Nb2O5-Fe2O3(BTNF)基陶瓷的晶体结构和介电性能的影响.XRD分析表明:La2O3掺杂陶瓷的(200)和(002)晶面衍射峰都发生了明显分裂,说明陶瓷均以四方相为主晶相.随着La2O3含量的增加,四方率先增大后减小.用SEM研究La2O3对BTNF基陶瓷微观结构的影响,结果表明:随着La2O3掺杂量的增加,试样的晶粒明显变小,La2O3显著的抑制了晶粒的生长.当La2O3掺杂量为0.15 mol;时,陶瓷晶粒生长比较均匀.陶瓷的室温介电常数大体上呈现出先增大后减小的趋势,当La2O3掺杂量为0.15 mol;时,有最大介电常数4562.