Yan Wenbo

OH ¡ absorption bands of LiNbO3 with varying composition ⁄

This paper reports that OH i absorption bands of lithium niobate crystal have been measured at room temperature, and the band shape depending on the crystal composition has been observed. The OH i absorption bands are fltted with three Lorentzian peaks by varying position, halfwidth, and height. Nearly constant peak positions (3468, 3481 and 3490 cm i1 ) are obtained for all samples. It shows that the height and area of the decomposed peaks vary with the Li composition in a complex way. However, the combinations of these fltting parameters show a linear dependence on the composition up to nearly 50 mol%, which is very useful for the composition determination in a wide range. The linear relationships between the parameter combinations and Li composition are also presented quantitatively. In addition, the explanations were given for the excellent composition linearity of parameter combinations.

Infrared studies of oxygen-related complexes in electron-irradiated Cz-Si

This paper investigates the infrared absorption spectra of oxygen-related complexes in silicon crystals irradiated with electron (1.5 MeV) at 360 K. Two groups of samples with low [Oi] = 6.9 × 1017 cm-3 and high [Oi] = 1.06 × 1018 cm-3 were used. We found that the concentration of the VO pairs have different behaviour to the annealing temperature in different concentration of oxygen specimen, it is hardly changed in the higher concentration of oxygen specimen. It was also found that the concentration of VO2 in lower concentration of oxygen specimen gets to maximum at 450 °C and then dissapears at 500 °C, accompanied with the appearing of VO3. For both kinds of specimens, the concentration of VO3 reachs to maximum at 550 °C and does not disappear completely at 600 °C.

Study on UV-light-induced absorption in LiNbO3:Fe, Co crystal

In this paper, the temporary UV-light-induced absorption in LiNbO3:Fe, Co crystal is investigated for different UV intensities. It is found that the sensitizing process in LiNbO3:Fe, Co can be considered as a combination of two sub-processes with different time constants. Based on the lattice structure and the photochromic mechanism of the material, the two sub-processes are suggested to arise from electron transfer from O2− to Fe3+ through two paths with different distances. The two-colour recording experiment in LiNbO3:Fe, Co is also preformed by using UV and green light as gating and writing beams respectively. High sensitivity is obtained in the recording, which is considered as the consequence of direct charge transfer from O2− to Fe3+.