We have observed intense line spectra in the neighborhood of 1.54 μm from erbium-implanted samples of 4H, 6H, 15R, and 3C SiC. Samples were implanted to a fluence of about 1013 erbium ions/cm2 using four implant energies. An anneal at 1700 °C in a SiC cavity was used. The temperature dependence of the integrated luminescence intensity from 1.49 to 1.64 μm varies very little from 2 to 400 K. No major differences are found for the spectra of the hexagonal and rhombohedral polytypes but there is a difference for cubic SiC (3C SiC).

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With a Fourier-transform spectrometer, especially developed for nuclei with weak NMR signals, the lines of 89y have been investigated in aqueous solutions of Y(NO3)3, YC13, and Y(C104) 3. The concentration dependence of the chemical shifts of the 89y resonance frequencies in these solutions were measured. Using this dependence, the Larmor frequency of the 89 y3 + ion solely surrounded by water was determined by extrapolation. The Larmor frequency of 89y was referred to those of 2H, 39K, and 73Ge with high accuracy. The magnetic moment of the agy3+ ion purely surrounded by H20 molecules is #(sgy3+)= -0.136 852 3 (4) #N. The concentration dependence of Y(NO 3) 3 solutions in D 20 yields the solvent isotope effect 3(89Y 3+ in D20)-cS(89Y 3+ in H20)=-(4.3+0.5)ppm. The S9y relaxation times T 1 and T 2 of a 3 molal aqueous Y(NO3) 3 solution were determined in the pH range-0.5... +1.25. T~=190...90s is nearly constant in this range, whereas the transverse relaxation rate T2-1 increases strongly with increasing pH; this effect seems to be due to the chemical exchange of the hydrated y3+ ion between a monomer and a polymer site.

A model is introduced which describes the electrical properties of a grain boundary under electron irradiation. The barrier height lowering under e‐beam irradiation of selected grain boundaries is determined by admittance measurements and can be described in the framework of the model presented. Admittance and EBIC measurements at differently processed grain boundaries (annealed, solar processed) are not uniformly correlated. Calculations based on our GB model indicate that the observed, partially diverging, trends of barrier heights and EBIC contrasts may be caused by the different levels of e‐beam irradiation at which admittance and EBIC are operated. A discrete trap level at Ev + 504 meV is generated at the grain boundary interface by intentional iron contamination. In this specific case, the electrical properties of the considered grain boundary are consistently described in the framework of our model by admittance and EBIC measurements.

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