Photoluminescence of InP:Zn

Photoluminescence spectra of diffusion layers of zinc-doped indium phosphide were investigated. A study was made of diffusion layers obtained in different regimes. A diffusion process was conducted for 30 and 60 min at temperatures of 450–500°C. The photoluminescence spectra consisted of bands with E₁=1.145 eV, E₂=1.37 eV, E₃=1.345 eV, E₄=1.15 eV. Photoluminescence was measured at 77 K upon excitation by laser radiation at 0.44 μm. An analysis is made of the regularities of the change in the spectral dependences for samples with different prehistories by using layer-by-layer etching as well as of the change in the integral Zn activation energy for different temperatures of postdiffusion annealing. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 125–128, January–February, 1997.     

Photoluminescence of ZnS:Cu crystals at various concentrations of copper

Doping of ZnS crystals with background impurities and ZnS:Al crystals by various concentrations of copper from a bismuth melt has been carried out. The photoluminescence spectra of the starting ZnS crystals annealed in the bismuth melt and doped by copper have been investigated. Interpretation of the experimental results according to the model in which the associates (Cu _Zn ^′ Cu _i ^● ) are responsible for the B-Cu band (≈460 nm) and the donor—receptor pairs [Cu _i ^● -(Cu _Zn ^′ Cu _i ^● )] are responsible for the G-Cu band (≈505 nm) is given. It is assumed that doping by copper from a bismuth melt is accompanied by the separation of a Cu_xS-type phase. It has been shown that heat treatment of ZnS crystals in the Bi melt does not lead to the appearance of luminescence centers based on Bi_Zn, Bi_S, and Bi_i. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 794–798, November–December, 2005.     

InGaN/GaN多量子阱热退火的拉曼光谱和荧光光谱

通过拉曼光谱及荧光光谱测量研究了采用低压金属有机化学沉积(MOCVD)方法生长的InGaN／GaN多量子阱高温快速热退火处理对量子阱光学性质的影响。观测到退火后InGaN／GaN量子阱的拉曼光谱E2,A1(LO)模式的峰位置出现了红移,而且该振动峰的半高宽也有微小变化。温度升高退火效果更明显。退火使量子阱内应力部分消除,同时In,Ga原子扩散出现相分离使拉曼谱表现出变化。在常温和低温下的光荧光谱表明,退火处理的量子阱发光主峰都出现了红移;而且低温退火出现红移,退火温度升高相对低温退火出现蓝移;同时在低温荧光光谱里看到经过退火处理后原发光峰中主峰旁边弱的峰消失了。讨论了退火对多量子阱光学性质的影响。     

温度对CdSe/znS量子点吸收光谱和光致发光谱的影响

测量了分散于正己烷溶液和甲苯溶液中的CdSe/ZnS量子点在室温到近溶液沸点温度间的吸收与光致发光光谱,比较了两种不同的CdSe/ZnS量子点的光谱特性,讨论了温度对吸收和光致发光光谱峰值波长以及相对强度的影响。结果表明:在25~100℃范围内,CdSe/ZnS量子点激子吸收峰波长有微小红移,最大约为4nm;光致发光光谱峰值波长略有红移,但最大不超过6nm。根据光致发光光谱测量的结果,确定了Varshni定律中关于CdSe/ZnS量子点禁带宽度的两个经验参数:α=(2.0±0.2)×10^-4eV/K和β=(200±30)K。温度对CdSe/ZnS量子点吸收强度影响不大,荧光发射强度与温度呈线性关系增强。     

热蒸发法Zn／ZnO叶状微米结构自组装生长及其发光特性

采用热蒸发法在ZnO缓冲层覆盖着Si衬底上合成了2D叶状的Zn晶枝结构,Zn的晶枝长度约为几十微米,厚度约为200nm,随后Zn晶枝在O2的气氛下热处理,在晶枝表面获得纤细、均匀的ZnO纳米线。晶枝按照无催化、自组装、汽相生长模式生长,晶枝最快生长方向是沿着载气气流的方向释放凝固潜热,XRD分析结果结果显示了Zn纳米线具有六角纤锌矿结构,Zn/ZnO的发光谱显示,在380nm处有一弱的UV近带边发射和中心在505nm处的强绿光发射,绿光发射归因于施主/受主对之间的辐射跃迁。     

Spectra of Manganese Emission Centers in Zinc Sulfide

We have investigated the photoluminescence of zinc sulfide single crystals doped with manganese and obtained from a melt under a pressure of argon. The structure of the crystals is the microtwin of sphalerite with a great number of packing defects. It is shown that the radiation spectrum consists of several individual overlapping bands, fundamental of which are the bands with maxima at 557, 578, 600, and 637 nm.     

聚丙烯腈纳米纤维毡上生长ZnSe纳米晶的结构及发光特性

通过静电纺丝制备聚丙烯腈(PAN)纳米纤维毡,采用水热法在二乙烯三胺和去离子水的混合溶剂中于180℃下制备ZnSe/聚丙烯腈纤维纳米毡复合材料。使用扫描电镜(SEM)、X射线衍射(XRD)、荧光光谱等分析方法对ZnSe/聚丙烯腈复合材料进行表征。结果表明,ZnSe/聚丙烯腈复合材料的形貌较复杂,既有直径10～100 nm,长度50～500 nm的纳米捧,也存在4～10μm左右的ZnSe微米花。260 nm波长光激发下ZnSe/聚丙烯腈复合材料的发射光谱包括位于351 nm(3.55 eV)的弱近紫外激子峰和位于427 nm(2.91 eV)的宽谱带缺陷发光峰,二者相对于ZnSe晶体的本征发射带468 nm均有明显的蓝移效应。     

金属离子修饰的ZnS/PAMAM纳米复合材料的荧光性能研究

用荧光分光光度法研究了Zn2+,Mn2+,Cd2+,Na+,K+,Ag+,Cu2+和Pb2+等金属离子修饰的ZnS/PAMAM树形分子纳米复合材料的荧光发射性能。结果表明：不同金属离子修饰效果不同。Zn2+,Mn2+和Cd2+修饰后,ZnS/PAMAM树形分子纳米复合材料的荧光发射强度有不同程度提高;Ag+,Cu2+和Pb2+的修饰对荧光有不同程度的猝灭作用;而Na+和K+的修饰对荧光发射无明显影响。与修饰前相比,Cd2+离子修饰的ZnS/PAMAM树形分子纳米复合材料标记的潜指纹发射的蓝色荧光更加明亮,与背景反差更加明显。这对提高潜指纹的显现精度和准确率有很好的借鉴价值。     

Mn2+, Pb2+共掺杂ZnS纳米材料制备及光致发光

采用聚乙烯基吡咯烷酮(PVP)为表面包覆剂,在室温大气条件下的水溶液中制备了ZnS:Mn,Pb纳米晶。讨论了Mn²⁺和Pb²⁺掺杂量对ZnS纳米发光材料光致发光强度的影响,确定了Mn²⁺和Pb²⁺掺杂量相对于Zn²⁺的最佳的量的比,并对其发光机理进行了初步的探讨。     

Temperature dependence of photoluminescence and electroluminescence of ZnS:Mn crystals

By means of comprehensive analysis of the temperature dependences of the photoluminescence for ZnS:Mn crystals, we have observed persistent changes in the intensity, shape, and position of the maximum in the emission spectrum associated with changes in the immediate environment of the manganese luminescence centers. We have also observed inflection points on the voltage vs. brightness characteristics of the samples, the position of which depends on the frequency of the exciting voltage and the temperature. The observed dependences are explained using concepts describing the mechanisms of pre-breakdown luminescence. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 631–636, September–October, 2006.     

稀土掺杂镝(Ⅲ)乙酰丙酮邻菲咯啉三元配合物的合成和荧光性质

合成了三个系列稀土掺杂镝乙酰丙酮(Hacac)邻菲咯啉(phen)三元配合物RE_xDy_1-x(acac)₃phen(RE=La,Y,Gd;x=0,0.10,0.20,0.30,0.50,0.70,0.90,1.00),通过紫外光谱、红外光谱、X射线粉末衍射对配合物进行了表征。对各系列配合物进行荧光光谱研究,发现La³⁺、Y³⁺、Gd³⁺对Dy³⁺离子均有荧光增敏作用,它们对Dy³⁺离子的荧光增强顺序为I(La³⁺)>I(Y³⁺)≈I(Gd³⁺)。当x=0.10~0.30,所有掺杂配合物的荧光强度都大于未掺杂的配合物Dy(acac)₃phen的荧光强度。     

低浓度掺杂CdSe/ZnS量子点光纤光致荧光光谱特性研究

制备了一种半导体量子点CdSe/ZnS低浓度掺杂的光纤,测量了不同掺杂浓度和不同光纤长度下光纤出射端的光致荧光光谱,分析了掺杂光纤长度和浓度对量子点光纤荧光光谱特性的影响.结果表明,与掺入光纤前相比,光纤中的量子点荧光发射峰值波长出现红移.在掺杂光纤长度为1~20 cm和掺杂浓度为(0.33~2.5)×10－2mg/mL的实验范围内,红移量随着掺杂光纤长度的增加和掺杂浓度的提高而增大.对给定的激励功率,荧光发射峰值强度对应有一个最佳的量子点光纤长度.对于给定的量子点光纤长度,荧光发射峰值强度对应有一个最佳的量子点掺杂浓度.     

氢等离子体气氛中退火多孔硅的表面和光荧光特性

用电化学腐蚀法制备了多孔硅(PS),在氢等离子体气氛中不同温度下对多孔硅样品进行了退火处理,并进行了光致发光(PL)谱和原子力显微镜(AFM)表面形貌的测量。不同退火温度给PS表面形态带来较大变化,也影响了其PL谱特性。在退火的样品中观察到的PL谱高效蓝光和紫光谱带,我们认为主要源于量子限制发光峰和非平衡载流子被带隙中浅杂质能级所俘获而引起的辐射复合所产生的。在420—450℃退火处理的多孔硅的PL谱上观察到了一个未见诸于报道的紫光新谱带(3．24eV,382nm),其发光机理有待于进一步研究。     

Deposition of ZnS thin film by ultrasonic spray pyrolysis: effect of thickness on the crystallographic and electrical properties

Zinc sulfide (ZnS) thin films have been deposited on Si (1 0 0) substrate using ultrasonic spray pyrolysis. X-ray diffraction (XRD) analysis revealed that the films are (0 0 2) preferentially oriented with c-axis-oriented wurtzite structure. The crystallinity has been found to improve with film thickness in the 180–6000 nm range. Film structure has been analyzed by XRD, scanning electron microscope, FTIR, and Raman spectroscopies, while the stoichiometry has been verified by energy-dispersive spectroscopy and particle-induced X-ray emission techniques. Electrical properties of the grown films were characterized by current–voltage and capacitance–voltage measurements where, the films show better conducting behavior at higher thickness.     

Absorption Spectra and Thermostimulated Luminescence of Irradiated KBr Crystals with a High Content of an Na Impurity

The influence of high concentrations of the Na⁺ impurity on the photo and thermostimulated luminescence in an xirradiated KBr crystal has been studied. It is revealed that at an impurity concentration of 1 mol.% the absorption spectrum of the KBr:Na crystal possesses only the bands belonging to the (, I _A) and (F, H _A) pairs of the centers and that the thermoluminescence spectrum consists of two peaks with a maximum at 140 and 165 K.     

离子注入及后退火方法制备SiO2基质中镶嵌ZnO纳米粒子的结构和光学性质

利用离子注入及后退火方法在光学纯的石英基片中注入3×1017cm-2剂量的Zn离子,然后在不同的退火条件下制备了高质量的镶嵌在SiO2基质中的ZnO纳米粒子.X射线衍射光谱的实验结果表明在氧气气氛、700℃退火温度和2小时退火时间条件下,得到了(002)择优取向镶嵌在SiO2基质中的ZnO纳米粒子;而在700℃退火温度、N2和O2气氛下顺次退火1小时,得到了比上述条件(002)择优取向更好的ZnO纳米粒子.室温下对用上述两种条件制备的镶嵌在SiO2基质中的ZnO纳米粒子观察到了自由激子吸收峰.室温光致发光谱中观察到了ZnO纳米粒子位于3.29eV处的强紫外发射,紫外发射强度与深能级发光强度之比为40,紫外发射峰的半高宽为96meV,晶体质量类似于分子束外延方法生长的ZnO.在低温(77K)光致发光谱中,较强的自由激子的紫外发光峰仍然存在.     

Distribution of Blue and Green Luminescence Centers in Barrier Regions of the Grains of Zinc Sulfide Electroluminophors

Based on the investigation of the spectra of two-photon excited luminescence of powder zinc sulfide electroluminophors, their electroluminescence spectra measured under different conditions at different stages of degradation, and also the data known from the literature dealing with the study of the microstructure of ZnS:Cu crystals, a conclusion has been drawn that the centers of green and blue luminescence are nonuniformly distributed over the luminophor grains. It is presumed that close by the surface of the grains, near the second phase–zinc–sulfide interface (the regions of energy barriers responsible for impact multiplication of charge carriers in prebreakdown electroluminescence) the centers of green luminescence predominate, while the blue luminescence centers are located at the periphery of the barriers, in deeper regions of the crystals.     

Effect of the order in which powdered ZnS is doped with copper chloride and indium on formation of luminescence centers

We consider the effect of the order in which In and CuCl impurities are added during thermal doping on the luminescence characteristics of ZnS, and also their role in formation of emission centers in zinc sulfide. We show that the order in which the impurities (acting as activators or coactivators) are added to the ZnS plays the determining role in formation of the spectral characteristics of the luminophore obtained. We have established that adding indium first during thermal doping of zinc sulfide with In and CuCl prevents diffusion of Cu into the interior of the ZnS. Adding indium after CuCl or adding indium simultaneously with CuCl prevents formation of the Cu2S and CuS phases or promotes degradation of the indicated phases in ZnS. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 601–605, September–October, 2006.     

EPR Spectra of Cr3+ Ions in Sr3Ga2Ge4O14:Cr Single Crystals

The results of investigations of chromiumdoped Sr₃Ga₂Ge₄O₁₄ single crystals by the EPRspectroscopy method are presented. It is shown that activating chromium ions form Cr³⁺ Ga³⁺ (Ge⁴⁺) substitution centers in the 1aoctahedral positions of the lattice of Sr₃Ga₂Ge₄O₁₄. Depending on the combination of occupation of the 3ftetrahedral positions of the first cationic coordination sphere by Ga³⁺ and Ge⁴⁺ ions, Cr³⁺ centers of two types are formed. Their individual magnetic spectra are characterized by axial and rhombic symmetry. The magnetic multiplicity of the axialsymmetry spectrum is equal to unity. There exist rhombicsymmetry centers of two types differing in the orientation of the principal magnetic axes and the value of the spinHamiltonian parameter E. The magnetic multiplicity of the individual magnetic spectra of rhombic centers of each type is equal to three. The detected EPR spectra of Cr³⁺ ions have been described by the spin Hamiltonian of rhombic symmetry. Its parameters and their spread have been determined.     

掺杂型BaFBr:Eu2+的热释发光性质的研究

BaFBr:Eu^2 是利用色心存储电子－空穴对并用可见光激励读出存储信息（产生Eu^2 的4f^65d→4f^7的跃迁）的优良的光激励发光材料。通过热释发光技术研究了BaFBr:Eu^2 的热激活行为，对其低温段和高温段的热释发光峰分别进行了归属，通过对BaFBr:Eu^2 以及掺杂Na^ 或Al^3 的BaFBr:Eu^2 的热释发光（TL）谱和光激励发光（PSL）谱的表征，指出在BaFBr:Eu^2 中掺杂Na^ 或Al^3 影响了F（Br^-）色心，使其陷阱深度变涛，并从理论上加以计算，得出的热致激发能量的变化与光致激光能量的变化能很好地吻合。