Effects of Illumination on Ar<Superscript>+</Superscript>-Implanted <Emphasis Type="Italic">n</Emphasis>-Type 6H-SiC Epitaxial Layers

Argon ions were implanted into n-type 6H-SiC epitaxial layers at 600°C. Postimplantation annealing was carried out at 1,600°C for 5 min in an Ar ambient. Four implantation-induced defect levels were observed at E_C-0.28 eV, E_C-0.34 eV, E_C-0.46 eV, and E_C-0.62 eV by deep level transient spectroscopy. The defect center at E_C-0.28 eV is correlated with ED₁/ED₂ and with ID₅. The defect at E_C-0.46 eV with a capture cross section of 7.8 × 10⁻¹⁶ cm² is correlated with E1/E2, while the defect at E_C-0.62 eV with a capture cross section of 2.6 × 10⁻¹⁴ cm² is correlated with Z1/Z2. Photo deep level transient spectroscopy was also used to study these defects. Upon illumination, the amplitudes of the deep level transient spectroscopy (DLTS) peaks increased considerably. Two emission components of Z1/Z2 were revealed: one fast and the other slow. The fast component could only be observed with a narrow rate window. In addition, a new defect was observed on the low-temperature side of the defect at E_C-0.28 eV when the sample was illuminated. [rl](Received ...; accepted ...)     

Designing Phase Selectively Soluble Polymer-Supports for Dimethylaminopyridine and Phosphine-Ligated Pd(0) Catalysts

Soluble poly(4-alkylstyrene) containing 4-methyl-, 4-tert-butyl, 4-dodecyl-, and 4-octadecylstyrene were formed either with monomers containing dyes-, ligands, or catalysts or with 5–10 mol% of 4-chloromethylstyrene and studied as supports for ligands or catalysts. Studies with dye-labeled polymers showed that polymers containing longer alkyl groups alone or at ca. 10 mol% loading are highly soluble in heptane can be used to separate and recycle organo- and transition metal catalysts.