Résultats exploitables Hydrogen in silicon Hydrogen is recognised as an important impurity in silicon, as a result of its ability to complete the chemical bonding of broken bonds at impurities or radiation-damage defects. This project concentrated on the interaction of hydrogen with radiation damage centres in silicon. Both neutron-irradiated and electron-irradiated silicon has been used, to provide a controlled source of vacancies, and hydrogen has been incorporated by diffusion or by the use of silicon grown in a hydrogen-rich atmosphere. A sequence of photoluminescence centres can be created in this material by neutron irradiation and annealing in the range 300 to 500°C. The centres, generically labelled 'B' centres, produce photoluminescence near the energy gap of silicon. We have shown that a very convenient description of the luminescence is obtained by considering the centres to trap excitons. Studies have been made of three of the B centres. First, measurements established the optimum conditions to generate the different defects, as reported in the published papers [1,2]. To obtain the high spectral resolution required for these studies, extensive use has been made of Fourier transform spectrometers (in London) and Fabry-Perot interferometers (in Moscow). Theoretical studies of the excited states have been approached using an elegant symmetry-based approach (by the Moscow workers) and by a conceptually simpler approximation (by the London workers). The results of these two approaches are in substantial agreement. A separate study has been made of vacancy-related using mid-infrared optical studies. Again studies have been made to generate sufficiently high concentrations of the different vacancy centres, with one, two, three and four H atoms in the vacancy [3]. Fourier transform spectrometers have been used in this study (at Århus). A thorough experimental and analytical analysis has been reported, allowing the frequencies of vibration of the H-atoms to be understood [3]. Recherche de données OpenAIRE... Une erreur s’est produite lors de la recherche de données OpenAIRE Aucun résultat disponible
