Single Crystal Host Research Articles

Electronic energy levels of Er3+ in ZnInGaS4:Er3+ single crystal and its site symmetry

ZnInGaS 4 and ZnInGaS4:Er3+ single crystals were grown using the CTR technique. The single crystals grown have a layered crystal structure. These compounds have both a direct and an indirect energy gap. Eight distinctive emission peaks of the ZnInGaS4:Er3+ single crystal were observed at 10 K. These photoluminescence peaks were attributed to the radioactive decay among the 4f split electron energy levels of the Er3+ ions that occupy the C2v site symmetry of the ZnInGaS4 single crystal host lattice.

Intrasectoral Zoning of Proteins and Nucleotides in Simple Crystalline Hosts

ABSTRACTOriented gases of biopolymers in simple, single crystal hosts might be used to measure anisotropic molecular properties of analytes that could not otherwise be crystallized. Here we show two types of crystals as examples of the single crystal matrix isolation of biopolymers: green fluorescent protein in α-lactose monohydrate as a model system for studying the kinetic stabilization of biopharmaceuticals, and adenosine phosphates in potassium dihydrogen phosphate, a first step in the matrix isolation of oligonucleotides. In each case, the hosts undergo compositional zoning – both intersectoral and intrasectoral – during growth from solution. Intrasectoral zoning is evident by the selective luminescence of adjacent vicinal slopes of growth active hillocks. Nucleotides furthermore distinguish between symmetry related growth sectors enantioselectively.

Kinetic Stabilization of Biopolymers in Single-Crystal Hosts: Green Fluorescent Protein in α-Lactose Monohydrate

Kinetic Stabilization of Biopolymers in Single-Crystal Hosts: Green Fluorescent Protein in α-Lactose Monohydrate

Quantum size effect in the excitonic luminescence of CsPbX 3-like quantum dots in CsX ( X = Cl, Br) single crystal host

Luminescence of CsPbX 3-like quantum dots in CsX crystal host ( X = Cl, Br) is reported. Single band spectrum is found for as grown or heavily annealed ( T = 240 °C) CsX:Pb, while a family of emisssion bands is observed after annealing at temperatures below 210 °C. Anisotropie growth of quantum dots in the early stage is proposed and positions of emission peaks are calculated for CsPbCl 3 quantum dots using a simple model.

Order and Disorder in Semiconductors

The pervasive impetus of modern semiconductor technology has become an accepted fact. Scientific mastering of materials and processes has increased tremendously within a short time frame. Technological control has been derived from this scientific base. An industry with more than $100 billion worth of silicon devices per annum in 1994 as well as incredibly high growth rates of production and applications is an economic reality in addition to being a matter of international industrial policy. The materials aspect of using perfected single crystals and applying local doping control provides the basis of this unusual success. Earlier usage of materials differed remarkably. Bronze and steel are used for their specific bulk properties. Shaping and connecting pieces is at the heart of iron-age or bronze-age technologies. Integration inside a regular spatial array of a host crystal is the semiconductor principle. The “Royal Road” to modern microelectronics consists of initially procuring a perfected single-crystal host, then locally establishing electrical and optical properties inside the host by specific replacements of host atoms by foreign “dopants.” The somewhat disparaging expression of defect as a generic term for all deviations from the host perfection does not really convey the power of this “doping doctrine” for semiconducting materials. The early pioneers of germanium and silicon however, placed great emphasis on the experimental verification that n-type and p-type doping by elements of the adjacent columns in the periodic table were accompanied by changes in the lattice parameter with atomic substitution of the host atoms as the guiding principle.

Optical properties of undoped and Co-doped SbSBr and BiSBr single crystals

SbSBr, BiSBr, SbSBr:Co and BiSBr:Co single crystals were grown by the Bridgman technique. The grown single crystals crystallize in an orthorhombic structure and have an indirect band structure. The temperature dependence of the optical energy gap for the single crystals shows anomalies at the first and second-order phase transition points. Cobalt dopants are located at the Td symmetry point in the host single crystals as Co2+ and Co3+ ions. Impurity optical absorption peaks due to the electron transitions between the energy levels of the Co2+ and Co3+ ions are observed.

OPTICAL PROPERTIES OF UNDOPED AND Ni-DOPED SbSBr AND BiSBr SINGLE CRYSTALS

SbSBr, BiSBr, SbSBr:Ni, and BiSBr:Ni single crystals were grown by the Bridgman technique. The grown single crystals crystallized in an orthorhombic structure and have an indirect band structure. The temperature dependence of their optical energy gap shows an anomalous property at the first order phase transition temperature and at the second order one. Nickel doped as an impurity site at the T d symmetry point in the host single crystals as Ni 2+ ion. The impurity optical absorption peaks appeared by the electron transitions between the energy levels of these ions.

Micro-Raman study Bi 2Sr 2CaCu 2O 8+δ single crystal intercalated with zinc phthalocyanine

The detailed micro - Raman measurements on Bi 2Sr 2CaCu 2O 8+δ (Bi-2212) single crystal (host) intercalated with zinc phthalocyanine, ZnPc (guest) has been carried out. Observed spectral changes due to intercalation have been related to charge-transfer processes and consequent semiconducting phase formations in the host oxide.

Influence of Intercalation on The Electrophysical Properties of Layered Semiconductors Bi2Te3 and InSe

The Li and Ba atoms were intercalated into the van der Waals gaps of Bi 2 Te 3 , solid solutions based on Bi 2 Te 3 and β-polytype of InSe single crystals of nand p-types. The temperature dependence of resistivity, the Hall effect and the Shubnikov- de Haas effect were investigated in host single crystals and after an inter calation. The intercalation of metallic atoms causes a change in carrier concentration and hence, the Fermi energy. The intercalated Bi 2 Te 3 samples possess the same six-ellipsoidal Fermi surface as the host material 2D weak localisation was observed in the host n-InSe which was suppressed by an intercalation

Zero-field splitting of Cm3+ in LuPO4 single crystals.

Electron-paramagnetic-resonance (EPR) spectroscopy has previously been employed in investigating excited levels of the ground-state manifold of the 5${\mathit{f}}^{7}$-configuration ion ${\mathrm{Cm}}^{3+}$ diluted in single crystals of the tetragonal-symmetry, zircon-structure hosts ${\mathrm{LuPO}}_{4}$ and ${\mathrm{YPO}}_{4}$. The three intradoublet resonances that were observed in these earlier studies, however, were significantly broadened due to radiation damage arising from the use of the 18.1-yr half-life isotope $^{244}\mathrm{Cm}$. In the present work, the isotope $^{248}\mathrm{Cm}$ (${\mathit{T}}_{1/2}$=3.4\ifmmode\times\else\texttimes\fi{}${10}^{5}$ yr) with a significantly lower specific activity has been incorporated in ${\mathrm{LuPO}}_{4}$-host single crystals in order to reduce the internal radiation-induced damage that can broaden both EPR and optical transitions. By employing these $^{248}\mathrm{doped}$ ${\mathrm{LuPO}}_{4}$ samples, it has been possible to observe an additional interdoublet transition for ${\mathrm{Cm}}^{3+}$, to perform more accurate measurements of the various intradoublet transitions at higher microwave frequencies, and to obtain optical absorption and fluorescence data for this system. These EPR and optical results have led to a more complete and accurate determination of the energy-level structure of ${\mathrm{Cm}}^{3+}$. Additionally, it has been possible to detect magnetic resonance transitions for the ${\mathrm{Cm}}^{3+}$ ion at room temperature.

Growth of oxygen deficiency-free YVO 4 single crystal by top-seeded solution growth technique

In spite of its excellent properties, yttrium orthovanadate (YVO 4) laser host single crystal has not been successfully adopted into high-tech applications because of crystal growth difficulties in connection with oxygen loss. This work is the first to apply a top-seeded solution growth (TSSG) technique to YVO 4, by which oxygen deficiency-free crystals can be directly grown. Since undesirable non-pentavalent vanadium oxides are continuously forming during the YVO 4, growth process, the flux media, in addition to the conventional TSSG requirements, must prevent the formation of oxygen deficient yttrium vanadate crystals. From these multiple requirements, lithium metavanadate (LiVO 3) was selected as the best solvent for YVO 4 flux growth. LiVO 3 has suitable solubility for YVO 4, low viscosity, low vaporization without toxicity (in the 1200–1400°C working temperature range), and the oxygen deficient Li-V bronze (γ-LiV 2O 5) can easily form in it, thus preventing oxygen defect formation in the yttrium vanadate crystals. Wanklyn's model and Viting and Timofeeva's calculation data were applied successfully for preliminary selection of the flux material. From the schematic V 2O 5-Li 2O-V 2O 3 ternary and Y 2O 3-V 2O 5-Li 2O-V 2O 3 quaternary systems, the phase relations of Li-V bronzes and YVO 4 can be resolved much more easily than from the previous simple binary systems. The transparent, macro-defect-free single crystal sample grown by the TSSG technique illustrates the significance of these considerations and the promise of this growth technology for YVO 4 crystals.

Electron paramagnetic resonance ofPu3+andCf3+in single crystals ofLuPO4

Electron-paramagnetic-resonance (EPR) spectroscopy has been used to investigate the ground-state properties of the actinide ions Pu[sup 3+] (5[ital f][sup 5]) and Cf[sup 3+] (5[ital f][sup 9]) incorporated as dilute impurities in single crystals of the tetragonal-symmetry host LuPO[sub 4]. The [ital g] values of the electronic ground states were determined experimentally at a sample temperature of 4 K. These values are compared to those calculated using the free-ion parameters available from previous crystal-field analyses of Pu[sup 3+] and Cf[sup 3+] ions diluted in LaCl[sub 3]-host single crystals and a set of crystal-field parameters reported earlier for Cm[sup 3+] (5[ital f][sup 7]) ions in LuPO[sub 4]. These crystal-field parameters were obtained from spin-Hamiltonian parameters using operator-equivalent factors and the assumption that the zero-field splitting of the ground state of the 5[ital f][sup 7] ion is due primarily to intermediate-coupling effects. The relatively poor agreement between the experimental and calculated [ital g] values indicates that the crystal-field parameters obtained for Cm[sup 3+] in LuPO[sub 4] cannot be used to predict the correct electronic ground-state properties of the other actinide ions Pu[sup 3+] and Cf[sup 3+] in the identical host single-crystal LuPO[sub 4]. Accordingly, in the case of actinide impurity ions in singlemore » crystals, there is no simple correspondence between the spin-Hamiltonian parameters and the crystal-field parameters.« less

An investigation of the indole/dibromobenzene mixed single crystal system using zero- and low-field optically detected magnetic resonance

The triplet-state properties of indole as a guest in a mixed single crystal host of 1,4-dibromobenzene (DBB) were investigated by using high-resolution optical spectroscopy and optically detected magnetic resonance (ODMR). We find two resolved origins for the phosphorescence at 4.2 K, with 0,0-bands occuring at 413.56 and 414.41 nm. The two origins are shown to correspond to two different orientations of indole within the host lattice. Each site exhibits distinctly different zero-field splittings (ZFS) and decay Kinetics

Pressure tuning of spectral holes in organic crystalline materials: Irreversible effects

The behavior of spectral holes under pressure in a polycrystalline material, namely dimethyl-s-tetrazine (DMST) doped n-octane was investigated and compared with the behavior in a durene single crystal host and glasses. Application of pressure induces frequency shifts and line broadenings which are significantly larger than in single crystals and glasses. Part of the broadening is irreversible and is attributed to the creation of dipolar strain fields. The distribution of dislocation thresholds is continuous with no obvious lower cut off. The response of the material to pressure changes depends on its history.

Influence of Intercalation by Metallic Atoms on the Shubnikov -de Haas Effect and the Energy Spectrum of Bi2Te3

Li and Ba atoms are intercalated into the van der Waals gaps of Bi2Te3 single crystals of n- and p-types. The resistivity, the Hall effect, and the Shubnikov-de Haas effect are investigated in host single crystals and after intercalation. It is found that the scattering of carriers is connected preferentially with acoustic phonons and does not change after intercalation. The intercalation of metallic atoms causes a change in the carrier concentration and hence, the Fermi energy. The intercalated samples possess the same six-ellipsoidal Fermi surface as the host material. [Russian Text Ignored].

Energy spectrum of Bi 2Te 3 intercalated by Li and Ba

The Li and Ba atoms were intercalated into the Van der Waals gap of Bi 2Te 3 single crystals of n- and p-types. The resistivity, the Hall effect and the Shubnikov-de Haas effect were investigated in host single crystals and after an intercalation. The scattering of carriers is connected preferentially with acoustic phonons and does not change after intercalation. The mobility does not fall after intercalation as it does after doping the samples. The intercalation of metallic atoms causes the change in carrier concentration and, hence, the Fermi energy. But the intercalated samples possess the same energy spectrum as the host material.

Epitaxial clusters in single crystal hosts

It is a general phenomenon for single crystal hosts that insoluble materials precipitate in the form of epitaxially aligned clusters. Such precipitates (or inclusions) are therefore coherently aligned and offer a unique model system for X-ray diffraction studies. In this paper, the general phenomenon of epitaxial clusters is discussed, and specific X-ray experiments on krypton as well as lead clusters in aluminum are presented. A hypothesis for the origin of epitaxial alignment is described and interfacial roughening is discussed. Also discussed is superheating and supercooling at the melting transition.

Quadrupole moments of isomeric states in 213Fr and 212Fr

TDPAD measurements of electric quadrupole coupling constants were performed for high-spin isomers in 213Fr and 212Fr using single crystal Tl hosts. Using measured quadrupole moments of states in Po and At nuclei and considering explicitly the octupole vibrational coupling, a universal effective charge has been derived. Using the calculated value Q( 213 Fr( 29 2 + )) = 70 (7) e· fm 2 to determine the electric field gradient for Fr in Tl, the quadrupole moments Q( 212 Fr(15 −)) = 84 (13) e· fm 2 and Q( 212 Fr(27−)) = 173 (33) e· fm 2 are derived.

Determination of the deuteron quadrupole coupling tensor in the photo-excited triplet state of dibromobenzophenone by electron spin echo envelope modulation

Highly resolved EPR transitions displaying deuteron hyperfine effects in di- p-bromobenzophenone in a single crystal host have been recorded with the technique of electron spin echo envelope modulation (ESEEM). Orientation dependence of the observed line positions under variation of the external magnetic field in the crystallographic a, c-plane yielded the magnetic dipolar and deuteron quadrupole coupling matrices for deuterons at two positions in the molecule. The strong orientational dependence of the line intensities in the Fourier-transformed ESEEM decay could be fully accounted for by calculating the echo modulation amplitudes numerically, using these matrices.

Nuclear magnetic moment of 106Rh.

Nuclear orientation and nuclear magnetic resonance measurements have been performed for $^{106}\mathrm{Rh}$ oriented at low temperature in iron and nickel hosts. From the results of the temperature dependence measurements of nuclear orientation, the magnetic moment of $^{106}\mathrm{Rh}$ was deduced as \ensuremath{\Vert}\ensuremath{\mu}${(}^{106}$Rh,${1}^{+}$)\ensuremath{\Vert}=2.52(5)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$, which is very different from the value of 3.07(9) ${\ensuremath{\mu}}_{N}$ reported previously. From the nuclear magnetic resonance on oriented nuclei measurements of $^{106}\mathit{Ni}$, the magnetic hyperfine splitting frequency \ensuremath{\Vert}g${\ensuremath{\mu}}_{N}$${B}_{\mathrm{HF}/\mathrm{h}\mathrm{\ensuremath{\Vert}}}$ was determined to be 441.5(7) MHz. Using the hyperfine field ${B}_{\mathrm{HF}}$ (RhNi) of -22.49(5) T, the precise value of the magnetic moment of $^{106}\mathrm{Rh}$ was deduced: \ensuremath{\Vert}\ensuremath{\mu}${(}^{106}$Rh,${1}^{+}$)\ensuremath{\Vert} =2.575(7) ${\ensuremath{\mu}}_{N}$. The electric quadrupole interaction has been measured using modulated adiabatic passage on oriented nuclei in a nickel single-crystal host. A broad distribution of the quadrupole splitting \ensuremath{\Delta}${\ensuremath{\nu}}_{Q}$ is found, extending from 0 to 300 kHz.