摘要:

AbstractThis is meant to be a brief overview of the developments of research activities in Japan on organometallic compounds related to their use in electronic and optoelectronic devices.The importance of organometallic compounds in the deposition of metal and semiconductor films for the fabrication of many electronic and opto‐electronic devices cannot be exaggerated. Their scope has now extended to thin‐film electronic ceramics and high‐temperature oxide superconductors. A variety of organometallic compounds have been used as source materials in many types of processing procedures, such as metal–organic chemical vapor deposition (MOCVD), metalorganic vapor‐phase epitaxy (MOVPE), metal–organic molecular‐beam epitaxy (MOMBE), etc. Deposited materials include silicon, Group III–V and II–VI compound semiconductors, metals, superconducting oxides and other inorganic materials.Organometallic compounds are utilized as such in many electronic and optoelectronic devices; examples are conducting and semiconducting materials, photovoltaic, photochromic, electrochromic and nonlinear optical materials.This review consists of two parts: (I) research related to the fabrication of semiconductor, metal and inorganic materials; and (II) research related to the direct use of organometallic materials and basic fun

ISSN:0268-2605    

DOI:10.1002/aoc.590050403

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractFour novel cobalt(III) complexes with a cyclopentadienyl or pentamethylcyclopentadienyl ring and dmit or dmio ligands were synthesized, and their electrochemical behaviour was investigated. All these complexes exhibited three one‐electron transfer steps: one reduction and two oxidation steps. In addition, a novel organosulphur compound was afforded by electrochemical oxidation of dmit cobalt complex. Thus, these complexes may have considerable synthetic potential as precursors for electron reservoirs and organosulphur compound

ISSN:0268-2605    

DOI:10.1002/aoc.590050404

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractRecent results are reviewed on synchrotron radiation (SR)‐excited photochemical reaction studies aimed at applications to semiconductor processes. Valence or core electronic excitations induced by SR irradiation and ensuing chemical reactions are classified and characterized by rate equations. Unique material selectivity in etching has been found. SiO2has been found to evaporate by SR irradiation and this phenomenon can be applied to the low‐temperature surface cleaning of silicon. In the epitaxial growth of Silicon by ultrahighvacuum chemical vapor deposition using Si2H6, SR irradiation significantly lowers growth temperature beyond the low‐temperature limit of thermal reaction. Lowering of the operating temperature by SR irradiation is especially effective in applications to the atomic layer epitaxial growth of silicon. The layer‐by‐layer process has been successfully demonstrated, confirming self‐limiting adsorption of SiH2Cl2and ensuring surface reactivation by SR

ISSN:0268-2605    

DOI:10.1002/aoc.590050405

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe photolysis of iron carbonyl (Fe(CO)5) adsorbed on titanium dioxide (TiO2, anatase) was studied by FT‐IR spectroscopy. When adsorbed Fe(CO)5is illuminated by visible and near‐UV light, the IR spectrum of its photolysis products is hardly observed, indicating that most of the Fe(CO)5is photodecomposed to iron(0) or iron oxides on TiO2. The carbon monoxide (CO) evolution rate upon illumination depends on the wavelength of light; 433 nm light is more effective for CO evolution than 366 nm light. This result implies that the band‐gap excitation of TiO2has little effect on the photolysis of adsorbed Fe(CO)5, since the absorption edge of TiO2(anatase) lies at around 400 nm. The effects of substrates on the photolysis of adsorbed Fe(CO)5are discussed with reference to previous results obtained for aluminium oxide (Al2O3) and silicon dioxide (SiO2), on which the photolysis leads to the formation of Fe2(CO)9or Fe3(

ISSN:0268-2605    

DOI:10.1002/aoc.590050406

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe photodissociation dynamics of organometallic compounds (tetramethyltin, trimethylgallium, trimethylindium and dimethylzinc) adsorbed on a quartz substrate at 100 K have been studied by time‐of‐flight mass spectrometry, detecting mainly CH3photofragments. Shapes of the time‐of‐flight spectra depend on the flux of the dissociation laser at 193 nm and the thickness of multilayers of organometallic compounds. In thick layers, not only a low energy component but also a high energy component are observed in the time‐of‐flight spectrum of the CH3photofragments. In thin layers, relaxation processes take place so quickly that the product time‐of‐flight profiles are characterized by a Maxwell–Boltzmann te

ISSN:0268-2605    

DOI:10.1002/aoc.590050407

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractQuadratic nonlinear optical properties for the crystalline powders of two types of ruthenium‐bipyridine [Ru(bipy)3] complexes were investigated. The nonlinear optical processes markedly depended on the molecular structures of the ruthenium complexes. Second harmonic generation (SHG) and very weak two‐photon emission were observed for the alkylated ruthenium‐bipyridine compexes with two long alkyl chains attached via amide bonds (RuCnB), whereas only two‐photon emission was observed for Ru(bipy)3. The existence of two amide bonds in one bipyridine ligand for RuCnB complexes most probably enhanced the molecular hyperpolarizability as compared with Ru(bipy)3. The SHG intensity from RuCnB complexes increased in the order RuC18B

ISSN:0268-2605    

DOI:10.1002/aoc.590050408

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractPhotochemical formation of colloidal silver, colloidal gold and silver‐gold (Ag‐Au) composite colloids under mild conditions has been studied. Irradiation of either aqueous AgCIO4or HAuCI4solution in the presence of sodium alginate (SA) with 253.7 nm light yielded colloidal silver or gold, whose particle diamter was 10‐30 nm or 40‐60 nm, respectively. The Ag‐Au composite colloids consisting of mixtures of silver and gold domains (particle diameter 30‐150 nm) have been prepared and their extinction spectra have been examined on the basis of a conventional Mie theory in combination with an effective medium theory to estimate the optical constants of these colloids. It has been shown that the extinction spectra of the Ag‐Au composite colloids are completely different from those of Ag‐Au alloy colloids, in that the former have two extinction maxima close to the colloidal extinction bands of pure silver and gold, in contrast to a single extinction maximum of the latter. The importance of natural, high‐molecular carboxylic acids such as alginic acid in the photochemical formation of metal colloids and thin films

ISSN:0268-2605    

DOI:10.1002/aoc.590050409

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractDissociation processes of the organoaluminum compounds Al2(CH3)6and Al2(CH3)3Cl3have been studied in the range of valence and Al:2pcore‐level ionization by means of photoelectron–photoion and photoion–photoion coincidence techniques. The double‐ionization threshold and the Al:2pcore‐ionization threshold of Al2(CH3)6are estimated to be about 30 and 80 eV1 eV = 96.4853 kJ mol−1.respectively. The relative yields of the H+Al+and H+CHm,+(m′= 0–3) ion pairs are enhanced around the Al:2pcore‐ionization threshold of Al2(CH3)6. The photoion–photoion coincidence intensities of Al2(CH3)3Cl3are negligibly small throughout the energy range studied. The ratio of the relative yield of AlC2H6+to that of Al+increases smoothly through the Al:2pcore‐ionization and/or excitation region of Al2(CH3)3Cl3. The variation of the fragmentation pattern with photon energy is discussed in conjunction with the r

ISSN:0268-2605    

DOI:10.1002/aoc.590050410

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe thermal decomposition of trimethylgallium [(CH3)3Ga] and triethylgallium [(C2H5)3Ga] on gallium arsenide (GaAs) surfaces was studied under an ultra‐high vacuum using mass spectrometry. It was observed that the decomposition process of (CH3)3Ga and (C2H5)3Ga depends on the arsenic coverage of the substrate surface. On a (100)‐oriented surface, increasing the arsenic coverage basically enhances the decomposition of (CH3)3Ga and (C2H5)3Ga to gallium atoms above 350 and 300°C, respectively. The decomposition of (CH3)3Ga proceeds by emitting CH3radicals. On a surface with low arsenic coverage, the decomposition of (CH3)3Ga is imperfect and fewer than three methyl groups of alkylgallium are desorbed. On a (111)B‐oriented surface, however, an increase in the surface arsenic coverage suppresses the decomposition of alkylgallium, which is different from the case for a (100) s

ISSN:0268-2605    

DOI:10.1002/aoc.590050411

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractIn photochemical vapor deposition of aluminum film on silicon using dimethylaluminum hydride, (CH3)2AlH, a surface reaction dominated below a (CH3)2AlH pressure of 0.3 m Torr at 200°C, which was induced only with the 160 nm band emitted from a deuterium lamp. A gas‐phase reaction occurred above 0.3 mTorr at 200°C, which could be induced by both 160 nm and 240 nm emission bands from the lamp. To distinguish between surface ad gas‐phase reactions, a thickness profile was used. At 240°C the surface reaction could be induced even by the 240 nm band, while the deposits formed under illumination of the two bands were thinner than those obtained with only the 240 nm band, indicating occurrence of vacuum ultraviolet (VUV)‐enhanced desorption. The mechanism responsible for the observed wavelength dependence in unclear. The electrical resistivity of the films deposited at 200°C was 4.5 μΩ cm, which did not change with

ISSN:0268-2605    

DOI:10.1002/aoc.590050412

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY