GaN/metal/Si heterostructure fabricated by metal bonding and laser lift-off

A process methodology has been adopted to transfer GaN thin films grown on sapphire substrates to Si substrates using metal bonding and laser lift-off techniques. After bonding, a single KrF （248 nm） excimer laser pulse was directed through the transparent sapphire substrates followed by low-temperature heat treatment to remove the substrates. The influence of bonding temperature and energy density of the excimer laser on the structure and optical properties of GaN films were investigated systemically. Atomic force microscopy, X-ray diffraction and photoluminescence measurements showed that （1） the quality of the GaN film was higher at a lower bonding temperature and lower energy density; （2） the threshold of the energy density of the excimer laser lift-off GaN was 300 mJ/cm^2. The root-mean-square roughness of the transferred GaN surface was about 50 nm at a bonding temperature of 400 ℃.

JOINING MECHANISM OF FIELD-ASSISTED BONDING OF ELECTROLYTE GLASS TO METALS

Investigations of technological characteristics and bonding mechanism of field-assisted bonding are done, which are for bonding of electrolytes (Pyrex glass) to monocrystal silicon and aluminum. The features of microstructure and the distribution of the diffused elements in the bonding interface area are studied by means of SEM, EDX and XRD, and the influence of the technological factors on the bonding process is also studied. The model of 'metal-oxides-glass' of bonding structure and ions diffusion and bonding in the condition of electrical field-assisted are indicated.

Germylene-Fe complexes caused by heterometallic coupling and investigation into the 3d-4p bonding

The interpretation of heterometallic bonding nature is a basic work of inorganic chemistry.By means of intermetallic substitution of germylene anions with iron halide complexes CpFe(CO)_(2)I andβ-diketiminato Fe^Ⅱchloride,the ferrogermylene complexes 3a,3b and 4a were synthesized and structurally characterized.The structural and IR characterizations show the presence of the Ge←Feπbackbonding in molecules 3a,3b and 4a.The computational works on frontier molecular orbitals and their comparison of energy states confirmed thatσdonation andπbackbonding are both weak in these molecules,despite three complexes have longer Ge-Fe bonds,whose strength decreases slightly with the degressive electron density around Fe environment in a sequence from 3a,3b to 4a.

Syntheses and Structural Characterizations of η~5-2,4-Cyclopentadien-1-yl Di-carbonyliron Heteronuclear Bi-Metallic Complexes

The novel complexes, Cp(CO) 2FeTiCp 2Cl(1) and Cp(CO) 2FeSn(CH 2CMe 2Ph) 3(2), were synthesized and characterized by means of elemental analyses and IR spectra, Cp(CO) 2FeSn· (CH 2CMe 2Ph) 3 was additionally characterized by X ray crystal structure analysis. The results of the elemental analyses are in good agreement with the theoretical values. The IR spectra show the existence of η 5 2,4 cyclopentadien 1 yl, carbonyl and methyl groups in the title complexes. The above experimental results show that the M-M bond exists in Cp(CO) 2FeSn· (CH 2Me 2Ph) 3, while the existence of the M-M bond in Cp(CO) 2FeTiCp 2Cl is highly possible, too. Both the two complexes are rather stable towards air and moisture, easily soluble in tetrahydrofuran and toluene, while their solubilities are greatly different in n hexane.

Synthesis of Novel Polymer-Bonded Water-Soluble Metal Porphyrins

The reaction of 5, 10, 15, 20-tetra-(4-pyridyl) porphyrin 1 with triruthenium dodecacarbonyl [Ru3(CO)12], zinc(II) acetate, copper(II) acetate, cobalt(II) acetate afforded complexes 2a?2d respectively. Treatment of 2a?2d with Merrifield’s peptide resin obtained 3a?3d. The compounds 3a?3d reacted with methyl iodide respectively gave 4a?4d. New complexes 4a?4d have been identified by IR, UV-visible spectra, and AES.

AROMATIC BOND INCLUDING METALLIC ATOM IN COORDINATE COMPOUNDS AND SOME OF ITS PROPERTIES

Aromatic bond including metallic atom (Ni) is investigated by EHMO calculation.The NMR spectra and the mechanism for hydrolysis are discussed on the ground of results of computation.

Charge transport and bipolar switching mechanism in a Cu/HfO_2/Pt resistive switching cell

Bipolar resistance switching characteristics are investigated in Cu/sputtered-HfO_2/Pt structure in the application of resistive random access memory（RRAM）.The conduction mechanism of the structure is characterized to be SCLC conduction.The dependence of resistances in both high resistance state（HRS） and low resistance state（LRS） on the temperature and device area are studied.Then,the composition and chemical bonding state of Cu and Hf at Cu/HfO_2 interface region are analyzed by x-ray photoelectron spectroscopy（XPS）.Combining the electrical characteristics and the chemical structure at the interface,a model for the resistive switching effect in Cu/HfO_2/Pt stack is proposed.According to this model,the generation and recovery of oxygen vacancies in the HfO_2 film are responsible for the resistance change.

Mathematical modeling and simulation of the interface region of a tri-layer composite material,brass-steel-brass,produced by cold rolling

The object of this study was to find the optimum conditions for the production of a sandwich composite from the sheets of brass-steel-brass. The experimental data obtained during the production process were used to validate the simulation program, which was written to establish the relation between the interface morphology and the thickness reduction amount of the composite. For this purpose, two surfaces of a steel sheet were first prepared by scratching brushing before inserting it between two brass sheets with smooth surfaces. Three sheets were then subjected to a cold rolling process for producing a tri-layer composite with various thick- nesses. The sheet interface after rolling was studied by different techniques, and the bonding strength for each rolling condition was determined by peeling test. Moreover, a relation between interfacial bonding strength and thickness reduction was found. The simulation results were compared with the experimental data and the available theoretical models to modify the original simulation program with high application efficiency used for predicting the behavior of the interface under different pressures.

Synthesis and properties of ionic conduction polymer for anodic bonding

In this study,powders of polyethylene oxide（PEO） and lithium perchlorate（Li Cl O4） were used as the raw materials for producing the ionic conduction polymer PEO–Li Cl O4 with different complex-ratios and used for anodic bonding through high energy ball milling method,and meanwhile,X-ray diffraction,differential scanning calorimetry（DSC）,ultraviolet absorption spectrum test analysis,and other relevant methods were adopted to research the complexation mechanism of PEO and Li Cl O4 and the impact of the ionic conduction polymer with different complex-ratios on the anodic bonding process under the action of the strong static electric field.The research results showed that the crystallization of PEO could be effectively obstructed with increased addition of Li Cl O4,thus increasing the content of PEO–Li Cl O4 in amorphous area and continuously improving the complexation degree and the room-temperature conductivity thereof,and that the higher room-temperature conductivity enabled PEO–Li Cl O4 to better bond with metallic aluminum and have better bonding quality.As the new encapsulating material,such research results will promote the application of new polymer functional materials in micro-electromechanical system（MEMS） components.

A two-dimensional microporous metal–organic framework for highly selective adsorption of carbon dioxide and acetylene

Solvothermal reaction of 3-aminoisonicotinic acid（Haina） and Cu（NO_3）_2·2.5H_2O gave a novel twodimensional（2D） microporous metal–organic framework, [Cu（aina）_2（DMF）]·DMF（1, DMF = N,N-dimethylformamide）. Single-crystal X-ray crystallographic study of compound 1 revealed that Cu（II）ions are linked by ainaàligands forming square grid-like layers, which stack together via multiple hydrogen bonding interactions. The solvent-free framework of 1a displayed considerable porosity（void = 46.5%） with one-dimensional（1D） open channels（4.7 ？ ？ 4.8 ？） functionalized by amino groups.Gas sorption measurements of 1 revealed selective carbon dioxide（CO_2） and acetylene（C_2H_2） adsorption over methane（CH_4） and nitrogen（N_2） at ambient temperature.

Synthesis and Characterization of β-Cyclodextrin Bonded Metal Porphyrins

Reactions of 5-(p-aminophenyl)-10, 15, 20-triphenyl porphyrin (1) withRu_3(CO)_(12) or M(OCOCH_3)_2 (M= Ni, Mn) afforded metalloporphyrins (4―6), respectively.6-Deoxy-6-io-do-β-cyclodextrin (2) and mono (6-O-trifluoromethanesulfonyl) pennethylatedβ-cyclodextrin (3) reacted with complexes 4―6 to give β-cyclodextrin bonded metal porphyrins(7―9) and permethylated β-cyclodextrin bonded me-tal porphyrins (10―12) respectively. These newcomplexes were identified by MS, IR, UV-visible and ~1H NMR spectra, and elemental analysis.

Atomically Precise Insights into Metal–Metal Bonds Using Comparable Endo-Units of Sc_(2) and Sc_(2)C_(2)

The precise identification of metal-metal bonds is critical to fully understanding the nature of metal-metal bonding but remains a fundamental challenge.Herein,we show the essence of Sc-Sc bonds with a metal-metal distance of 3.36 Å in a C_(3v)(8)-C_(82) fullerene cage using crystallography.

Coordination of neighboring C——H bond to transition metal center——III. Study on localized molecular orbitals of the binucleate ion [Fe_2(CH_3)(CO) (Ph_2pCH_2PPh_2)Cp_2]^+

A localized INDO method was used to calculate the ion [Fe_2 (CH_3) (CO) (Ph_2PCH_2PPh_2)- Cp_2]^+. Based on the analysis of the localized molecular orbitals (LMO), bond orders and contour maps, it was pointed out that the LMO no. 20 corresponds to the coordination of C(1)-H(I) σbond to Fe(2) atom. Non occurrence of metal-metal bond between Fe(1) and Fe(2) atoms was found and the covalence of irons was numerated, which coincides with the value in ref 17.

Improved light extraction of wafer-bonded AlGalnP LEDs by surface roughening

By using the wafer bonding technique and wet etching process,a wafer bonded thin film AlGaInP LED with wet etched n-AlGaInP surfaces was fabricated.The morphology of the etched surface exhibits a pyramid-like feature.The wafer was cut into 270×270μm2 chips and then packaged into TO-18 without epoxy resin.With 20-mA current injection,the light intensity and output power of LED-Ⅰwith surface roughening respectively reach 315 mcd and 4.622 mW,which was 1.7 times higher than that of LED-Ⅱwithout surface roughening.The enhancement of output power in LED-Ⅰcan be attributed to the pyramid-like surface,which not only reduces the total internal reflection at the semiconductor-air interface but also effectively guides more photons into the escape angle for emission from the LED device.