Doping of silicon with magnesium is investigated by a sandwich diffusion technique. Temperature dependence of the diffusion coefficient in the dislocation-free silicon in the range of 1000-1200 8C is determined. It obeys the Arrhenius behavior over the range of 600-1200 8C, when the data obtained earlier for the lower temperatures are taken into consideration. Preliminary results on Mg diffusion in the dislocated crystals are also presented. The dislocation-free Si:Mg samples are investigated with the Hall-effect measurements and the low-temperature Fourier spectroscopy. A decrease in concentration of Mg interstitials (about 15%) has been observed after 31 months of the samples storage at room temperature, when a commercially available FZ silicon was used as a starting material. The effect of the samples degradation is proposed to be due to a formation of Mg-O complexes. When using a special silicon purified from oxygen and carbon with concentrations below or equal to 1.5 Â 10 14 and 5 Â 10 14 cm À3 , respectively, a decrease in the density of interstitial magnesium has not been noticed during this period. The storage of Si:Mg samples prepared from pure silicon gives rise to the formation of an unknown center, whose ionization energy is between the corresponding values for the interstitial Mg 0 centers and (Mg-O) 0 complexes.
The speed of conversion of infrared (IR) images by a planar semiconductor gas discharge system into the visible range has been investigated. Argon or nitrogen are used in the discharge gap having an electrode distance of 100 μm. Using pulse radiation from an IR laser to excite the system, we have shown that the characteristic response time of the device with the cryogenic discharge in the gap can lie in the submicrosecond range. This characteristic of the system can be applied for a fast IR imaging at a rate higher than 106 frame/s.
The deep double donor levels of substitutional chalcogen impurities in silicon have unique optical properties which may enable a spin/photonic quantum technology. The interstitial magnesium impurity (Mgi) in silicon is also a deep double donor but has not yet been studied in the same detail as have the chalcogens. In this study we look at the neutral and singly ionized Mgi absorption spectra in natural silicon and isotopically enriched 28-silicon in more detail. The 1s(A1) to 1s(T2) transitions, which are very strong for the chalcogens and are central to the proposed spin/photonic quantum technology, could not be detected. We observe the presence of another double donor (Mgi * ) that may result from Mgi in a reduced symmetry configuration, most likely due to complexing with another impurity. The neutral species of Mgi * reveal unusual low lying ground state levels detected through temperature dependence studies. We also observe a shallow donor which we identify as a magnesium-boron pair.arXiv:1806.01965v3 [cond-mat.mtrl-sci]
The possibility of making the breakdown delay time shorter in a micro-discharge (MD) system has been analysed. The delay time is controlled by passing through the system a low current from a dc voltage source. The delay time strongly depends on this bias current. In the presence of the control current, the time distribution of the breakdown probability shows two quite different characteristic times. This feature is due to the specific spontaneous dynamics of the MD system at low controlling current densities. The results obtained are important for determining the operation mode of high-speed MD devices.
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