Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 14: II-VI semiconductors I
HL 14.1: Vortrag
Dienstag, 28. März 2006, 11:00–11:15, POT 151
Magnetic field studies of bound exciton complexes in Lithium doped ZnO — •Rob McKenna1,2, Markus R. Wagner1, Axel Hoffmann1, Joachim Sann3, Stefan Lautenschläger3, and Bruno K. Meyer3 — 1Intitute for Solid State Physics, Technical University Berlin — 2University of Technology Sydney — 3I. Physics Institute, Justus Liebig University Giessen
Lithium located at the Zn site in the ZnO matrix could be a valid acceptor for p-conduction. Our magneto-PL and -PT investigation of a Lithium doped ZnO film on a ZnO substrate found I6 to I8, as well as I0 and I1 bound exciton complexes, with the smallest FWHM of 80 µ m. Zeeman-splitting of peaks up to 580 µ eV at 5 T, produced electron g-values in good agreement with previous publications. An additional splitting of peaks in magnetic fields stronger than 3 T, was also clearly apparent. A non-zero an-isotropic hole effective g-value for B⊥ c is discussed as the possible origin of the observed splitting. The neutral or ionised nature of the I0 and I1 bound exciton complexes in the magnetic field was also further clarified and the appearance of a new peak on the lower energy side of the I1 peak, indicating zero-field-splitting, was also investigated. In addition to this, the forbidden exciton could be observed. Temperature dependent measurements were employed to investigate the donor or acceptor character of the bound exciton complexes and angular and polarisation dependent measurements clarify whether the involved holes originate from a valence band with Γ7 or Γ9 symmetry.