Volume 101, Issue 9, 01 May 2007
Index of content:
101(2007); http://dx.doi.org/10.1063/1.2713947View Description Hide Description
We report the electroluminescence(EL) of organic heterojunction devices based on -diphenyl--bis(3-methylphenyl)-(-biphenyl)-,-diamine (TPD) and 2-(-biphenyl)-5-(-tert-butylphenyl)-1,3,4-oxadiazole (PBD). Besides monomolecular emissions from TPD, there are two additional EL peaks at around 460 and from the bilayer device indium tin oxide (ITO)/. Our experimental data confirmed that the EL emission maximized at around is from electroplex as the result of charge carriers cross recombination at the TPD/PBD interface and the EL emission maximized at around originates from -type exciplex.
101(2007); http://dx.doi.org/10.1063/1.2721946View Description Hide Description
We report on the different behavior of electron and ion currents recorded by a Faraday cup in a plasma bunch generated via laser ablation. An excimer laser was employed to irradiate a Ge target. The current signals were recorded equipping the Faraday cup collector by a set of diaphragms. We found that the electron time-of-flight spectra were fairly similar to the ion ones, but the collected charge yield for electrons was up to 200 times larger than the corresponding ion yield. We ascribed such a discrepancy to the different cup collection efficiency for ions and electrons forming the plasma which was heavily influenced by the plume geometry, the energy of the particles, as well as the diaphragm size. Our findings would suggest that the overall electron charge “tended” to be collected, unlike the ion charge which scaled upon the collection solid angle.
101(2007); http://dx.doi.org/10.1063/1.2732403View Description Hide Description
The carrier lifetime of an quantum dot(QD) on an InP substrate is measured to be twice that of an QD on the same substrate, although the ground-state energy levels and barrier heights of these QDs are comparable. These differences are interpreted in terms of the smaller conduction band-offset in QDs compared to QDs.