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The formation of Si nanocrystallites (nc-Si) in erbium (Er)-dispersed Si[O.sub.x] films is examined by using in situ annealing and transmission electron microscopy measurements. The results have displayed that the formation of nano-Si region with the suitable size is vital for the enhancement of Er ion emission.

The B- or P-doped silicon (Si) crystals, treated with high concentration of H, are studied to analyze the dopant dependence of such complexes on passivation and reactivation of carrier after hydrogenation. The difference in the reactivation process for the p-type and n-type specimens is found to be basically because of the formation of H-related defects based on the stable sites of the hydrogen (H) atoms.

The formation of Si nanocrystallites (nc-Si) in erbium (Er)-dispersed SiOx (x≤2) films was investigated by in situ annealing while performing transmission electron microscopy measurements. The correlation between the formation of nc-Si and Er ion emissions was also comprehensively investigated by photoluminescence and electron spin resonance measurements. The results showed that the formation of nano-Si region with the suitable size is important for enhancement of Er ion emission. [ABSTRACT FROM AUTHOR]

The formation of Si nanocrystallites (nc-Si) in erbium (Er)-dispersed SiOx (x≤2) films was investigated by in situ annealing while performing transmission electron microscopy measurements. The correlation between the formation of nc-Si and Er ion emissions was also comprehensively investigated by photoluminescence and electron spin resonance measurements. The results showed that the formation of nano-Si region with the suitable size is important for enhancement of Er ion emission. [ABSTRACT FROM AUTHOR]

The phonon confinement and self-limiting oxidation effects of silicon nanowires (SiNWs) synthesized by laser ablation were investigated. The size of SiNWs was controlled by the synthesis parameters during laser ablation and the subsequent thermal oxidation. Thermal oxidation increases the thickness of the SiNWs’ surface oxide layer, resulting in a decrease in their crystalline Si core diameter. This effect causes a downshift and asymmetric broadening of the Si optical phonon peak due to phonon confinement, while excess oxidation causes an upshift due to compressive stress. The compressive stress retarded the oxidation of the SiNWs by self-limiting oxidation effect. This result shows that the Si core diameter can be controlled by compressive stress. [ABSTRACT FROM AUTHOR]

We investigated platinum (Pt)-related defects in silicon (Si) based on the measurement of their optical absorption and found optical absorption peaks related to Pt clusters. Pt and H were separately doped in FZ-Si by heating at 1000-1300 °C followed by quenching in water. Optical absorption spectra were measured at about 5 K with a Fourier transform infrared spectrometer. In a specimen doped with a higher concentration of H than of Pt, we observed optical absorption peaks due to four types of Pt-H complexes. In specimens with a higher concentration of Pt than of H, peaks were observed in the region from 1300 to 1700 cm[sup -1]. Based on the peak shift due to the hydrogen isotope and the dependence on excitation energy and the annealing behavior, these peaks are thought to be due to the electronic transitions of Pt-related defects such as Pt clusters, rather than the local vibrational modes of H. The defect centers which gave rise to optical absorption at about 1301, 1318, 1452, and 1474 cm[sup -1] were IR-active centers under illumination and the optical threshold energy was determined to be about 0.34 eV by applying Lucovsky's model [Solid State Commun. 3, 299 (1965)]. [ABSTRACT FROM AUTHOR]

The properties of many optical absorption peaks in electron-irradiated n-type Si crystals were studied. Specimens were prepared from various Si crystals. After chemical etching, they were irradiated with 3 MeV electrons at room temperature (RT). Their optical absorption spectra were measured with a Fourier transform infrared spectrometer at temperatures in the range of 7 K to RT with a resolution of 0.25 cm[sup -1]. Many optical absorption peaks were observed in the wave number range between 850 and 1600 cm[sup -1] only in n-type (phosphorus-doped) Si crystals. Hence, they are due to donors. Such peaks were very weak in Czochralski-grown Si (Cz Si) crystals. This suggests that these peaks are due to complexes of phosphorus and vacancies since most vacancies in Cz Si form pairs (A center) with oxygen because of the very high concentration of oxygen in those crystals. They disappeared as the result of annealing at above 175 °C. Temperature dependencies of intensities of various peaks were studied. [ABSTRACT FROM AUTHOR]

Neutron-irradiation-induced defects in hydrogenated Si were investigated by detecting optical absorption due to their complexes with hydrogen. Specimens were doped with hydrogen by heating in H[sub 2] gas at 1300 °C followed by quenching in water. They were then irradiated with neutrons. The optical absorption spectra were measured at about 5 K with a Fourier transform infrared spectrometer. We investigated the dopant dependence and the annealing behaviors of H–interstitial (I) and H–vacancy (V) complexes. From the dopant dependence, we classified the peaks observed as I-related complexes or V-related complexes. In the annealing experiment, we observed numerous peaks after annealing above 300 °C in the region from 1940 to 2040 cm[sup -1], whereas no such peaks were observed in the case of electron irradiation. This result shows that agglomerations of I and of V form more easily in neutron-irradiated Si than in electron-irradiated Si because of higher local concentrations of V and I in neutron-irradiated specimens. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]