Incorporation efficiency of carbon in GaAs using carbon tetrabromide in solid source molecular beam epitaxy
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
Authors: Sun, ZZ; Yoon, SF; Tan, KH; Zhang, R; Jiang, J
Abstract
The incorporation efficiency of carbon in GaAs using carbon tetrabromide (CBr4) was studied. A series of carbon-doped GaAs samples were grown at different CBr4 pressures and V/III ratios using solid source molecular beam epitaxy (SSMBE). The results showed a high carbon incorporation efficiency of similar to30% within the CBr4 pressure range up to 2 x 10(-7) Torr, which resulted in carbon doping concentration of up to 2 x 10(20) cm(-3). However, an increase in V/III ratio was found to reduce the carbon incorporation efficiency. Based on our experimental results, a kinetic model was developed to explain the effect of carbon incorporation in GaAs from CBr4 in SSMBE growth. The model incorporates the effects of different CBr4 decomposition rates on the As-covered and Ga-covered surface. (C) 2004 American Vacuum Society.
Metal-Involving Bifurcated Halogen Bonding C-Br center dot center dot center dot eta(2)(Cl-Pt)
CRYSTAL GROWTH & DESIGN
Authors: Dabranskaya, Uladzislava; Ivanov, Daniil M.; Novikov, Alexander S.; Matveychuk, Yury, V; Bokach, Nadezhda A.; Kukushkin, Vadim Yu
Abstract
The complexes trans-[PtCl2 (NCNR2)(2)] (R-2 = Me-2 1, Et-2 2, (CH2)(4) 3) were cocrystallized with CBr4 in CHCl3 (1 and 3) or in MeNO2 (2) forming adducts 1 center dot CHCl3 center dot CBr4, 2.2CBr(4), and 3.2CBr(4), respectively. In two out of three adducts, viz. 1 center dot CHCl3 center dot CBr4 and 2.2CBr(4), unique Br3C-Br center dot center dot center dot eta(2)(Cl-Pt) metal-involving bifurcated halogen bonding was detected, by single-crystal XRD, along with other halomethane-chloride interactions. Appropriate density functional theory calculations performed by two complementary methodologies, (i) single-point "quasi-solid state" calculations with topological analysis of the electron density distribution within the framework of Bader theory (QTAIM method) and (ii) Kohn-Sham calculations with periodic boundary conditions, confirmed the existence of the bifurcated interactions and their noncovalent nature. Estimated energies of these interactions vary from 1.1 to 4.7 kcal/mol.