Berlin 2005 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

HL: Halbleiterphysik

HL 44: II-VI Halbleiter IV

HL 44.5: Talk

Monday, March 7, 2005, 16:00–16:15, TU P-N201

Long-wavelength bound and unbound charge excitations in doped ZnO and ZnO based alloy thin films — •C. Bundesmann, M. Schubert, D. Spemann, H. v. Wenckstern, H. Hochmuth, E. M. Kaidashev, M. Lorenz, and M. Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, D-04103 Leipzig, Germany

Doping and alloying of ZnO with different materials opens the path to interesting properties, like n- and p-type conductivity, ferroelectricity, ferromagnetism or band-gap-engineering, with possible applications in optoelectronics or spintronics.

Raman scattering is a perfect tool to study optical phonons in doped or alloy thin films, with the potential use to identify dopant or alloy material incorporation in ZnO thin films. Infrared spectroscopic ellipsometry (IRSE) allows for the determination of free charge carrier parameters, such as density, anisotropic mobility, and eventually effective mass. IRSE is a potential candidate for characterization of complex ZnO based device heterostructures, as recently shown for group-III-nitride heterostructures. (N,Li,P,Sb,Ga,Al)-doped ZnO and (Mg,Cd,Mn,Ni,Co,Fe,Cu)ZnO alloy thin films are grown by pulsed laser deposition on sapphire substrates, and studied by Raman scattering and IRSE.[1] Experimental phonon modes are compared with MREI model and local mode calculation schemes.

[1] C. Bundesmann et. al, Appl. Phys. Lett. 81, 2376 (2002); 83, 1974 (2003); 85, 905 (2004);.