(C) 2011 American Institute of Physics. [doi:10.1063/1.3581159]“
“External quantum efficiency of semiconductor photonic devices is directly measured by wavelength-dependent laser-induced temperature change (scanning laser calorimetry) with very high accuracy. Maximum efficiency is attained at an optimum photo-excitation level that can be determined with an independent measurement of power-dependent temperature or power-dependent photoluminescence. Time-resolved photoluminescence lifetime

and power-dependent photoluminescence measurements are used to evaluate unprocessed heterostructures for critical performance parameters. The crucial importance of parasitic background absorption is discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580259]“
“We have theoretically investigated the properties buy Daporinad of electronic transport in graphene heterostructures,

which consist of two different graphene superlattices with one-dimensional periodic potentials. It is found that such heterostructures possess an unusual tunneling state occurring inside the original forbidden gaps, the electronic conductance is greatly enhanced and additionally, the PKC412 molecular weight Fano factor is strongly suppressed near the energy of the tunneling state. Finally, we present the matching condition of the impedance of the pseudospin wave for occurring the tunneling state by using the Bloch-wave expansion method. (C) 2011 American Institute of Physics. [doi:10.1063/1.3573492]“
“Tris (8-hydroxyquinolino)

aluminum (Alq(3)) films and their chemical failure process are investigated using x-ray photoelectron spectroscopy. We make sure Angiogenesis inhibitor that the O 1s spectrum of the pristine Alq(3) only has one component which is in contrast to the current controversy on this issue. Our experiments further indicate that the chemical failure process of Alq(3) holds the critical role to understand this problem. The chemical failure process also shows the organic carbon contamination and the replacement reaction between Alq(3) and water, ultimately resulted in the failure of the device. These fundamental results provide a basis understanding for future development of Alq(3)-based light emitting devices. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3562151]“
“4 Asymmetric resistive pulses caused by nanoparticles passing through tunable nanopores have been recorded and studied using a semianalytic physical model. Experiments used 220 nm diameter carboxylate-modified polystyrene spheres, electrophoretically driven through two elastomeric nanopore specimens. Asymmetry is evident both within the pulse full-width half-maximum and over a longer 5 ms window. This asymmetry is consistent with the near-conical pore geometry, and is greater for both large and slow-moving particles. Particle mobility did not increase with size, and was unexpectedly enhanced when the electrolyte pH was reduced from 8.