William S. Rees

Molecular design of dopant precursors for atomic layer epitaxy of SrS:Ce

Two cerium compounds, Ce{N[Si(CH 3 ) 3 ] 2 } 3 and Ce(tmhd) 4 (tmhd=2,2,6,6-tetramethylheptane-3,5-dionate), have been evaluated for utilization in the preparation of thin films of SrS:Ce by atomic layer epitaxy (ALE). The resultant coatings have been characterized for use in electroluminescent (EL) devices. The observed emission maximum at 518 nm for the devices derived from Ce(tmhd) 4 shifts to 480 nm for those resulting from Ce{N[Si(CH 3 ) 3 ] 2 } 3 . This shift may be correlated with the basicity of the ligand present on the dopant element.

Evaluation of Zn{N[Si(CH 3 ) 3 ] 2 } 2 as a p -type dopant in OMVPE growth of ZnSe

We have grown nominally undoped ZnSe on GaAs from the precursors H2Se and Et2Zn. Replacement of Et2Zn by Zn[N(TMS)2]2 produced crystalline ZnSe of a lesser quality. Data indicate incorporation of nitrogen into the films when Et2Zn is utilized as the main zinc source with Zn[N(TMS)2]2 being introduced at dopant levels. Characterization techniques employed include NMR, XRD, SIMS, SEM, PL, RGA, GC/MS, and Raman spectroscopy.

Mocvd Erbium Sourcesa

The overall objective of this research is to develop source materials for doping AIGaAs. We compared Er(C 5 H 5 ) 3 to Er{N[Si(CH 3 ) 3 ] 2 ) 3 for purity, decomposition kinetics and doping of germanium films deposited from Ge(CH 3 ) 4 in a hydrogen atmosphere. Cyclopentadienyl erbium left large amounts of carbon both in pure metal films, and in the germanium film, at low pressure and temperatures to 850°C. Bis-(tri-methylsilyl) erbium amide decomposed cleanly without carbon, nitrogen or silicon in the deposited film.

Cadmium bis(alkylthiolate) complexes as precursors for cadmium sulfide: a mild route to hawleyite

The preparation, characterization and thermolysis of Cd(SR)2(R = Pri, But, Bz), [Cd(SPri)2·1-methylimidazole] and {[Cd(SBz)2]2·1-methylimidazole} are reported. The volatile organosulfur reaction co-products were identified as RSR, or its subsequent secondary decomposition products. Hawleyite is formed from Cd(SBz)2 at 300 °C, 0.1 atm, 4 h; whereas the other two Cd(SR)2 examples produce the expected Greenockite.

MOCVD Growth of Copper and Copper Oxide Films from Bis -β-Diketonate Complexes of Copper. The Role of Carrier Gas on Deposit Composition.

An examination of thermal chemical vapor deposit elemental composition by EDAX has been completed for material films grown from Cu(acac) 2 and Cu(tmhd) 2 (acac = pentane-2,4-dionate; tmhd = 2,2,6,6-tetramethylheptane-3,5-dionate), using both hydrous and anhydrous carrier gas steams each of reducing (H 2 ), inert (H 2 ), and oxidizing (O 2 ) composition.

Electronic Properties of OMVPE Grown films of YBa 2 Cu 3 O 7-δ on 1” LaAlO 3 Substrates

Films of YBa 2 CU 3 O 7-δ have been grown on 1” LaAlO 3 by OMVPE utilizing M(tmhd) n (M = Ba, Cu: n = 2; M = Y: n = 3; tmhd = 2,2,6,6-tetramethylheptane-3,5-dionato) as the source materials in a cold wall, vertical rotating disk reactor. The resultant films were characterized by SEM, XRD, T c , J c , and surface profilometry measurements. Relative to laser ablated thin films, the surface morphology was determined to be virtually featureless. In-situ depositions at substrate temperatures of

Group 12 Thiolates: Syntheses, Characterization and Decomposition Pathways

Abstract : Zinc- and cadmium bis(alkylthiolate) compounds have been prepared and converted into the appropriate binary metal sulfides by thermal treatment. Several mercury chlorothiolates have been synthesized and characterized by single crystal X-ray diffraction. Their decomposition pathways are discussed. The prepared binary metal sulfides have been studied by XRPD and in selected cases - by particle size determination. The volatile co-products have been isolated and characterized by GC/MS. Group 12 thiolates, Metal sulfides, Decomposition pathways.

Preceramic Polymers for Aluminum Oxides

The utilization of recently discovered aluminum-oxygen-carbon backbone polymers in the preparation of various phases of A1 2 O 3 is presented. The structure of the polymers has been examined by ss 27 AI NMR, TGA, MS, SEM, XRD, and EDAX. The solid pyrolysis products of these polymers have been characterized by ss 27 AI NMR, XRD, SEM, and EDAX. The volatile products of pyrolysis have been studied by trapping, TGA and MS.

Initial Preparation of a Barium Bis(oligoetherthiolate): An Intramolecularly-Stabilized Precursor for the Thermally Mild Formation of BaS

Barium metal reacts with an oligoether thiol to form an organic solvent soluble dimeric metal bis(thiolate) compound, which gives crystalline BaS upon thermolysis at 220°C for two hours.

Organometallic chemical vapor deposition: The roles of precursor design and growth ambient in film properties

Examples of chemical control in CVD of metallic and ceramic films are highlighted. Specific attention is paid to the complexity of precursor design. The effect of reactor environment on growth chemistry is investigated. Examples where reducing or oxidizing atmospheres provide a high level of control over deposit composition are outlined. The system examined centers on yttrium and yttria. These materials are, in general, desired less for their optical or electronic properties and more for their structural properties. Thus, the rigid purity demands of the microelectronics industry are somewhat relaxed. Nevertheless, critical attention must be paid to the issues of vapor pressure and decomposition profile. Where sufficient data is available to justify it, some explaination of the issues relevent to vapor pressure is presented.