We demonstrate electroluminescence (EL) with an external efficiency of more than 0.1% at room temperature from glide dislocations in silicon. The key to this achievement is a considerable reduction of nonradiative carrier recombination at dislocations due to impurities and core defects by impurity gettering and hydrogen passivation, respectively, which is shown by means of deep-level transient spectroscopy. Time-resolved EL measurements reveal a response time below 1.8 μs, which is much faster, compared to the band-to-band luminescence of bulk silicon.

We investigated correlation between concentration of deep level defects at dislocations, detected by deep level transient spectroscopy (DLTS) and the efficiency of dislocation related luminescence in Si samples with dislocation density of about (3–5) × 108 cm–2. We show that significant reduction of concentration of deep states at dislocations achieved by using the combination of gettering and passivation, results in a drastic (by several orders of magnitude) increase of dislocation‐related D1 luminescence in a high temperature range. As a consequence, electroluminescence (EL) from dislocation related D1‐line reaches an external efficiency more then 0.1% at room temperature. Concentration of D1 and D2 luminescence centers, roughly estimated from the optical absorption spectrum, was found to be of the order of 3 × 1014 cm–3 for dislocation density of about 5 × 108 cm–2. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

To prove directly the relation between the emergence of narrow lines in the dislocation photo‐l uminescence spectrum of germanium after the second deformation stage and the splitting value Δ of perfect dislocations a special orientation of crystals at the second deformation stage is used. The samples contain dislocations either with Δ > Δ0 or with Δ < Δ0 (Δ0 is the equilibrium splitting value). The narrow lines are found to arise only on the short‐w ave side of the line corresponding to equilibrium splitting at Δ > Δ0 and on the long‐w ave side at Δ < Δ0. This result and the unique regularity of the narrow line arrangement observed experimentally are considered as a convincing evidence for the effect of the distance between partials on the radiation energy associated with the 90° partials only.

No abstract

No abstract

No abstract

No abstract

The data for the microhardness and fracture toughness of Y–Ba–Cu–O and Bi-based single crystals and ceramics in the temperature range 77–293 K are presented and analyzed. Our study reveals that the microhardness of high temperature superconductors is very sensitive to the oxygen stoichiometry, the phase composition, the temperature, and to the microstructural defects such as impurities, intergranular boundaries, and voids. Attention is drawn to the anisotropy of the micromechanical properties and to the features of the fracture in the vicinity of the indentation. The data available on the plasticity of Y–Ba–Cu–O and Bi–Sr–Ca–Cu–O from micro- and macrotests are compared.