Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DS: Fachverband Dünne Schichten

DS 15: Functional Oxides

DS 15.2: Hauptvortrag

Dienstag, 26. Februar 2008, 15:00–15:30, H 2032

ZnO-based Hetero- and Quantum Well Structures for Light-Emitting Applications — •Fritz Henneberger and Sergey Sadofev — Humboldt-Universität zu Berlin, Institut für Physik, Newtonstr. 15, 12489 Berlin

Molecular-beam epitaxial growth far from thermal equilibrium allows us to overcome the standard solubility limit and to alloy ZnO with MgO or CdO in strict wurtzite phase up to mole fractions of several 10 %. In this way, a band-gap range from 2.1 to 4.4 eV can be covered. For epitaxy on ZnO substrates, we observe rocking curve widths of the ternaries as small as 19 arcsec and pseudomorphic growth over several 100 nm. A clear layer-by-layer growth mode controlled by RHEED oscillations enables us the fabrication atomically smooth heterointerfaces and well-defined quantum well structures exhibiting prominent band-gap related light emission in the whole composition range. Strong built-in polarization fields are screened off by moderate optical pumping. On appropriately designed structures, laser action from the UV down to green wavelengths and up to room temperature is achieved. All these findings make ZnO-based heterostructures promising candidates for opto-electronic applications in the short-wavelength range.