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Luminescent properties of Eu'+ or Ce3+ doped Sffia~S4 powder samples are investigated over the temperature range 30 to 300 K. Up to 300 K the lifetime remains constant (TO = 480 and 24 ns for Eu '+ and Ce3+, respectively) showing that the probability of non-radiative transitions is negligible at room temperature. The decay of thin films prepared by reactive radio-frequency magnetron sputtering deviates strongly from an exponential one as a consequence of energy transfer to defects. Codoping of Ce3' with Na+ considerably increases the luminescence efficiency.Les proprittts luminescentes de poudres de SrGazS4 doptes au Eu2+ et au Ce3+ sont ttudites pour des temptratures variant de 30 h 300 K. Jusqu'h 300 K, les durkes de vie restent invariantes (zo = 480 et 24 ns pour Eu2+ et Ce3+ respectivement). Ceci montre que les probabilitts de transitions non-radiatives sont ntgligeables h la tempkrature ambiante. Le dtclin de couches minces prtpartes par pulvtrisation cathodique radio-frtquence est beaucoup plus rapide et montre la prbsence d'un transfert d'tnergie vers des dtfauts. Le codopage de SrGazS4 : Ce3+ avec du Na+ ambliore fortment le rendement de luminescence.

We propose a low-resistivity metal/Si/DySi2/Si multilayer Ohmic contact to n-type Si. For a DySi2 monolayer on n-type Si(111), the Fermi level has been found to be located only 0.08 eV below the conduction-band minimum of Si, corresponding to flatband conditions. Here, we demonstrate that this Fermi-level position is conserved to a large extent upon Si overgrowth of the monolayer, allowing us to exploit the flatband conditions for device applications under ambient conditions.

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The luminescence excitation and emission spectra of Znl -,Mn,S with high Mn concentration (0.01 2 x 5 0.25) is studied by time-resolved laser spectroscopy at temperatures 10 K 5 T 5 -5 300 K. Besides of the emission bands peaking a t G = 17000 cm-l, 5 = 15750 cm-l, and 5 = = 13500 cm-l a fourth band peaking in the I R at i; = 10600 cm-l is registered. This I R band is closely connected to two excitation bands in the UV peaking at G = 26900 cm-l and 5 = 28750 cm-l (T = 10 K, x = 0.034). Four different Mn dominated centers are distinguished, which are partly connected by energy transfer. Die Lumineszenz-Anregungs-und Emissionsspektren von Znl -,Mn,S rnit hoher Mn-Konzentration (0,Ol 5 x 5 0,25) werden rnit zeitaufgeloster Laserspektroskopie im Temperaturbereich von T = 10 bis 300 K untersucht. AuBer den bekannten Emissionsbanden mit Maxima bei G = = 17000 cm-l, 5 = 15750 cm-l und 5 = 13500 cm-l wird eine vierte Emissionsbande mit einem Maximum bei Y" = 10600 cm-l beobachtet. Diese IR-Bande steht in enger Verbindung zu zwei Anregungsbanden im ultravioletten Spektralbereich mit Maxima bei G = 26900 cm-l und 28750 cm-l (T = 10 K ; x = 0,034). Vier unter Teilnahme von Mn gebildete Lumineszenzzentren werden unterschieden, die teilweise durch Energietransportprozesse miteinander verbunden sind.