Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 26: II-VI semiconductors II
HL 26.10: Vortrag
Dienstag, 28. März 2006, 17:30–17:45, POT 51
A comparative study of the substrate influence on the structure of pulsed laser-deposited ZnO thin films — •Felice Friedrich, Ina Sieber, and Norbert H. Nickel — HMI Berlin, Abt. SE1, Kekuléstr. 5, D-12489 Berlin
Nominally undoped ZnO thin films were deposited by pulsed laser deposition (PLD) on different substrates, namely silicon, quartz, sapphire, and magnesium oxide. For better comparability ZnO was grown on all substrates simultaneously. The thickness of the resulting ZnO layers was about 1 µm. The chamber pressure was varied between 10−3 mbar and 3 mbar depending on the oxygen flow whereas the deposition temperature was held constant at 700∘C. The films were characterized using SEM and Raman backscattering spectroscopy.
With increasing pressure a transition from ZnO thin films to the formation of nanostructures was observed. Furthermore a strong influence of the substrate on the layer orientation and the degree of disorder in the ZnO films has been found. This is likely due to the respective lattice mismatch. Raman spectra of the films on quartz substrates show the recently controversially discussed additional local vibrational modes that were observed in doped ZnO thin films and amongst others related to the presence of nitrogen [1]. However, in connection with the SEM results we tend to assign these modes to disorder activated Raman scattering of the silent B1 modes in ZnO [2]. This will be discussed in detail.
[1] Haboeck et al., PSS (b) 242 (2005) R21
[2] Manjón et al., JAP 97 (2005) 053516