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We report an above-band-gap radiative transition in the photoluminescence spectra of single crystalline Ge in the temperature range of 20~296 K. The temperature-independence of the peak position at ~0.74 eV is remarkably different from the behavior of direct and indirect gap transitions in Ge. This transition is observed in n-type, p-type, and intrinsic single crystal Ge alike, and its intensity decreases with the increase of temperature with a small activation energy of 56 meV. Some aspects of the transition are analogous to III-V semiconductors with dilute nitrogen doping, which suggests that the origin could be related to an isoelectronic defect.

Addition of Me2GeCl2 to Li+ [(η5-C5H5)Re(NO)(PPh3)] gives the chiral rhenium dimethylchlorogermyl complex (η5-C5H5)Re(NO)(PPh3)(GeMe2Cl) (92%), which reacts with LiAlH, and Me3SiOTf to yield (n5-C5H5)Re(NO)-(PPh3)(GeMe2H) (74%) and (η5-C5H5)Re(NO)(PPh3)(GeMe2OTf) (3; 94%), respectively. Reactions of 3 and halide salts give (η5-C5H5)Re(NO)-(PPh3)(GeMe2X) (X=F, Br, I; 81–83%). All compounds exhibit two 1H/ 13C NMR signals for the diastereotopic GeMe 2 groups at ambient temperature, except 3 for which coalescence occurs at 211 K (Δ≠=9.6 ± 0.2 kcal/mol). This is interpreted as indicating a rapid equilibrium with the dimethylgermylene complex [(n5-C5H5)Re(NO)(PPh3)(=GeMe2)]+ TfO−.

Reaction of Me2GaCl and LiCCSiMe3 or R2GaCl (R  Me, tBu) and LiCCPh (benzene, 70°C) gives [Me2GaCCSiMe3]2 and [R2GaCCPh]2 in 62%, 58%, and 71% yields, respectively. The gallium acetylides were characterized by IR, Raman, and NMR (1H, 13C, 13C{1H}) spectroscopy. Reactions of the dimethylgallium acetylides and phosphines (R2PH; R  Et, iPr) (toluene, 110-20°C) give HCCSiMe3 or HCCPh and the corresponding dimethylgallium dialkylphosphides [Me2GaPR2]n (R  Et, n = 3, iPr, n = 2).

Reaction of Me2GaCl and LiCCSiMe3 or R2GaCl (R  Me, tBu) and LiCCPh (benzene, 70°C) gives [Me2GaCCSiMe3]2 and [R2GaCCPh]2 in 62%, 58%, and 71% yields, respectively. The gallium acetylides were characterized by IR, Raman, and NMR (1H, 13C, 13C{1H}) spectroscopy. Reactions of the dimethylgallium acetylides and phosphines (R2PH; R  Et, iPr) (toluene, 110-20°C) give HCCSiMe3 or HCCPh and the corresponding dimethylgallium dialkylphosphides [Me2GaPR2]n (R  Et, n = 3, iPr, n = 2).

The novel antimony source compound di-isopropylantimony hydride, (i-Pr)2 was synthesized and evaluated for use as a volatile Sb-source compound for low temperature growth of Sb-containing semiconductor materials. (i-Pr)2SbH was pyrolyzed in a horizontal atmospheric pressure organometallic vapor phase epitaxy (OMVPE) reactor using Arand H2 as carrier gases. The gaseous exhaust products were analyzed by a residual gas analyzer. Complete pyrolysis of (i-Pr)2SbH in our OMVPE reactor occursaround 300°C and 350°C in Ar and H2, respectively. A comparison between the pyrolysis temperatures and pyrolysis byproducts with respect to a proposed decomposition mechanism of (i-Pr)2SbH is presented. Sb films were grown on Si(100) andSi(111) as low as 200° C. The Sb films were analyzed by Auger and X-ray diffraction. These polycrystalline Sb films were free of detectable carbon by AES. X-ray diffraction data indicated that these Sb films were highly oriented in the [000L] direction.

New dialkylgallium dialkylphosphide compounds having the formula [(t- Bu)(R)GaPR'2]n (R = t-Bu, Me3SiC=C; R' = t-Bu, i-Pr, Et; n = 1, 2) were recently prepared and characterized. When R = R' = t-Bu, the compound is a low melting, monomeric solid. The other compounds are dimeric solids with the unsym-metrical acetylides occurring as cis and trans isomers. Polycrystalline gallium phosphide was deposited from these sources on silicon atlow pressure (0.05–0.1 Torr) and low temperature (350–600 °C) in a horizontal OMVPE reactor. The film growth was monitored by a residual gas analyzer and the by-products were trapped (N2(1)) to be later analyzed by 1H and 13C NMR. The deposited films were characterized by Raman spectroscopy, X-ray powder diffraction, and Auger emission spectroscopy.

Highly tensile-strained Ge thin films and quantum dots have the potential to be implemented for high mobility metal-oxide-semiconductor field-effect transistor channels and long-wavelength optoelectronic devices. To obtain large tensile strain, Ge has to be epitaxially grown on a material with a larger lattice constant. We report on the growth of tensile-strained Ge on relaxed InxGa1−xAs epitaxial templates by metal-organic chemical vapor deposition. To investigate the methods to achieve high quality Ge epitaxy on III–V semiconductor surfaces, we studied Ge growth on GaAs with variable surface stoichiometry by employing different surface preparation processes. Surfaces with high Ga-to-As ratio are found to be necessary to initiate defect-free Ge epitaxy on GaAs. With proper surface preparation, tensile-strained Ge was grown on relaxed InxGa1−xAs with a range of In content. Low growth temperatures between 350 and 500 °C suppress misfit dislocation formation and strain relaxation. Planar Ge thin films with ...

Reaction of Li+[(η5-C5H5)Re(NO)(PPh3)]− with Ph3GeCl and Ph2GeCl2 (THF, −75°C) gives germyl complexes (η5-C5H5)Re(NO)(PPh3)(GePh3) (84%) and (η5-C5H5) Re(NO)(PPh3)(GePh2Cl) (3, 82%), respectively. Reaction of 3 and (CH3)3SiOTf gives (η5-C5H5)Re(NO)(PPh3)(GePh2OTf) (4, 82%). Several properties show the triflate substituent in 4 to be extremely labile. First, reaction of 4 and pyridine to give [(η5- C5H5)Re(NO)(PPh3)(GePh2NC5H5)]+TfO− (5) is complete in