Blue light emitting diode internal and injection efficiency AIP Advances 2, 032117 (2012) Enhancement of hole injection and electroluminescence characteristics by a rubbing-induced lying orientation of alpha-sexithiophene J. Appl. Phys. 112, 024503 (2012) Study of field driven electroluminescence in colloidal quantum dot solids J. Appl. Phys. 111, 113701 (2012) Indium incorporation and emission properties of nonpolar and semipolar InGaN quantum wellsElectroluminescence from metal-insulator-semiconductor structures with silicon dioxide (SiO z ) layers containing varying amounts of excess silicon (Si) in the form of tiny Si precipitates have been studied in detail. Bulk insulator emission from the Si islands is shown to dominate over emission from either the Si0 2 matrix material or the metallic gate material by studies of oxide or metal gate material, voltage polarity, and insulator thickness dependencies. Several distinct spectral peaks are observed in the energy range from 1.5 to 5 eV which cannot be attributed to optical interference effects. The higher-energy peaks show a strong dependence on electric field relative to that at the lowest energy (1.7-2 eV). The entire spectral amplitude shows a strong dependence on high-tempera.ture annealing and excess Si content, decreasing drastically with increasing Si or decreasing annealing temperature. These results are shown to be consistent with light emission during electronic transitions between discrete energy levels associated with Si islands and/or their interface with the Si0 2 host matrix material. Quantum size effects, similar to those observed in semiconductor superlattices, are proposed as one possible explanation.

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The first observation of EPR of electrons at dislocations in Ge is reported. Under optical excitation two sets of lines are detected: four lines about the (111) axes within = 0.34 and g ± = 1.94, and 24 lines with g\\ = 0.73 and g L~ 1.89 about (111) axes with a sixfold 1.2° distortion. The lines persist for hours after excitation and are inverted in sign.PACS numbers: 76.30.Mi, 61.70.Le, 72.20.Jv

Cyclotron resonance has been optically detected in a GaAs/Ga067Aic33As superlattice with the wells doped with Si to 6&10 6 cm . The sign and magnitude of the signal depend on the emission monitored, and an effective mass of 0.062mo was obtained for the electrons. Because of the 1ow magnetic field' needed at 22 0Hz for cyclotron resonance, the confinement of the orbits is readily observed.