溶液法制备氧化锌晶体的微结构及发光特性研究

以醋酸锌和六次甲基四胺为原料在不同的溶液环境中,采用水热法或热溶液法合成了不同形貌的微纳氧化锌.氧化锌形貌和尺寸的控制对合成环境有强烈的依赖.通过化学吸附将乙二胺四乙酸二钠和柠檬酸吸附在氧化锌的极性面上,可以抑制极性面的晶体生长,调控氧化锌的晶体形貌.这种选择吸附性导致了样品形貌的不同.拉曼光谱测试结果表明,在柠檬酸溶液中合成的氧化锌的晶粒更小.光致发光光谱测试结果表明,所得到的氧化锌的发光是激子和缺陷发光.     

掺铁铌酸锂晶体中光致散射的锂组分和温度依赖关系研究

研究了单掺铁铌酸锂晶体的光致散射行为随锂组分以及温度的变化关系.实验表明,随晶体组分的升高,光致散射得到了大幅抑制;不同组分晶体光致散射被完全抑制的温度不同.由此提出掺铁铌酸锂晶体在48.9 mol%-49.3 mol%范围内可能存在一临界锂组分,当晶体组分超过这一临界组分时,晶体光致散射被大幅抑制,而光致散射行为的温度依赖关系明显改变.     

近化学计量比掺镁铌酸锂晶体的抗光折变性能

应用气相传输平衡技术,我们获得了3种近化学计量比掺镁铌酸锂晶体,晶体的掺镁量接近我们以前提出的第二阈值.在我们实验室所能达到的最大光强26 MW/cm2照射下,在所有近化学计量比掺镁铌酸锂晶片中没有观察到光斑畸变,该光强比同成分铌酸锂晶体所能承受的光强高6个量级,为目前已报道的铌酸锂晶体之最.应用双光束全息写入法测得掺1.0 mol% Mg近化学计量比铌酸锂晶体的光折变饱和值仅有4.6×10-7,比同成分铌酸锂晶体小两个量级,从已有实验数据推测,该晶体的抗光折变能力应当比同成分铌酸锂晶体高9个量级以上.     

高掺镁铌酸锂晶体OH~-吸收光谱的低温研究

本文测量了纯铌酸锂和高掺镁铌酸锂晶体的低温红外光谱,观察了OH-吸收峰的温度依赖特性.研究发现纯铌酸锂的OH-振动吸收峰基本不随温度而变化,而高掺镁铌酸锂晶体的OH-振动吸收峰的主峰峰位随温度的降低向高波数方向移动.通过分析两种晶体中不同的缺陷模型以及H+在晶格中的占位,我们提出高掺镁铌酸锂晶体中的H+紧邻高电性杂质缺陷(MgNb)3-分布,直接参与缺陷集团,完全不同于纯铌酸锂晶体中H+的分布情形,这造成了高掺镁铌酸锂晶体中OH-振动吸收峰随温度的变化.而集团内部缺陷之间相互作用随温度降低而增强的趋势是OH-振动吸收峰右移的主要原因.     

铁铪双掺铌酸锂晶体的光致散射研究

本文研究了铁铪双掺铌酸锂晶体的光致散射行为,对比了铁铪双掺铌酸锂晶体还原前后的光致散射结果.结果表明:晶体中的锂空位可使晶体暗电导增加并引起光致散射的泵浦光强阈值效应;高泵浦光强下产生的严重光致散射起源于晶体中的较高的三价铁离子浓度.铁铪双掺铌酸锂晶体具有较好的抑制光致散射的能力.     

Infrared studies of oxygen-related complexes in electron-irradiated Cz-Si

This paper investigates the infrared absorption spectra of oxygen-related complexes in silicon crystals irradiated with electron(1.5MeV) at 360 K.Two groups of samples with low [Oi]=6.9×1017cm 3 and high [Oi]=1.06×1018cm3 were used.We found that the concentration of the VO pairs have different behaviour to the annealing temperature in different concentration of oxygen specimen,it is hardly changed in the higher concentration of oxygen specimen.It was also found that the concentration of VO 2 in lower concentration of oxygen specimen gets to maximum at 450 ℃ and then dissapears at500 ℃,accompanied with the appearing of VO 3.For both kinds of specimens,the concentration of VO 3 reachs to maximum at 550 ℃ and does not disappear completely at 600 ℃.     

纯铌酸锂晶体红外光谱的低温研究

测量了同成分纯铌酸锂的低温红外光谱,发现低温下铌酸锂晶体将会出现位于3200 cm^-1左右的新红外吸收峰.研究发现该峰与晶体中的氢离子无关,并且其峰强和峰形都随温度的升高发生复杂的变化.基于上述实验结果,认为该峰应该起源于电子在相邻的小极化子（Nb⁴⁺_Li）和自由极化子（Nb⁴⁺_Nb）之间的跃迁.另外,通过拟合发现新红外吸收峰可分解成三个高斯峰,这三峰应归因于能量有细微差别的三种跃迁. 关键词： 铌酸锂 红外吸收光谱 杂质缺陷     

铌酸锂基光伏微流体操控技术

光伏微流体操控技术利用非均匀光伏电荷场对流体目标的静电作用来实现非接触操控。近年来,基于铌酸锂的光伏微流体操控技术逐渐引起人们的关注,并有望成为铌酸锂基生物光子芯片微流体操控功能的关键支撑技术。与传统的全电微流体操控和光镊操控相比,铌酸锂基光伏微流体操控不需要外部电源供电,不需要复杂电极的制备,所需操控光强低,作用范围广,因此可以最大程度地避免外界对内部生物环境的污染和干扰。本文介绍了铌酸锂基光伏微流体操控的理论基础,系统阐述了铌酸锂基光伏微流体操控的近期研究进展。     

Study on UV-light-induced absorption in LiNbO3:Fe, Co crystal

##正##In this paper,the temporary UV-light-induced absorption in LiNbO_3:Fe,Co crystal is investigated for different UV intensities.It is found that the sensitizing process in LiNbO_3:Fe,Co can be considered as a combination of two sub-processes with different time constants.Based on the lattice structure and the photochromic mechanism of the material,the two sub-processes are suggested to arise from electron transfer from O~(2-) to Fe~(3+) through two paths with different distances.The two-colour recording experiment in LiNbO_3:Fe,Co is also preformed by using UV and green light as gating and writing beams respectively.High sensitivity is obtained in the recording,which is considered as the consequence of direct charge transfer from O~(2-) to Fe~(3+).     

The effects of fast neutron irradiation on oxygen in Czochralski silicon

The effects of fast neutron irradiation on oxygen atoms in Czochralski silicon(CZ-Si) are investigated systemically by using Fourier transform infrared(FTIR) spectrometer and positron annihilation technique(PAT).Through isochronal annealing,it is found that the trend of variation in interstitial oxygen concentration([Oi]) in fast neutrons irradiated CZ-Si fluctuates largely with temperature increasing,especially between 500 and 700 C.After the CZ-Si is annealed at 600 C,the V4 appearing as three-dimensional vacancy clusters causes the formation of the molecule-like oxygen clusters,and more importantly these dimers with small binding energies(0.1-1.0eV) can diffuse into the Si lattices more easily than single oxygen atoms,thereby leading to the strong oxygen agglomerations.When the CZ-Si is annealed at temperature increasing up to 700 C,three-dimensional vacancy clusters disappear and the oxygen agglomerations decompose into single oxygen atoms(O) at interstitial sites.Results from FTIR spectrometer and PAT provide an insight into the nature of the [Oi] at temperatures between 500 and 700 C.It turns out that the large fluctuation of [Oi] after short-time annealing from 500 to 700 C results from the transformation of fast neutron irradiation defects.