Regensburg 2002 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 38: Poster 2
HL 38.48: Poster
Donnerstag, 14. März 2002, 16:30–19:00, Poster A
Electronic and structural properties of doped ZnO and (ZnMgCd)O thin films prepared by PLD — •Michael Lorenz1, Evgeni M. Kaidashev1,2, Holger v. Wenckstern1, Carsten Bundesmann1, Volker Riede1, Joerg Lenzner1, and Marius Grundmann1 — 1University Leipzig, Faculty of Physics und Geosciences, Institute for Experimental Physics II — 2Rostov-on-Don State University, Mechanics and Applied Mathematics Research Institute, Russia
The ZnO based wide bandgap materials become more and more interesting now due to possible applications as transparent front contacts in solar cells, or as transparent p-n junction in LEDs and laser diodes. As the base material, ZnO thin films doped with Al or Ga, or mixed with Mg or Cd have been grown by pulsed laser deposition PLD on c-plane sapphire substrates. An advantage of the PLD technique is its unique flexibility concerning the deposited material. Epitaxy of the ZnO thin films was improved by introducing a two-step growth process as confirmed by RHEED. The electronic and structural properties of the deposited thin film systems were extensively studied by Hall measurements, optical UV-VIS spectroscopy, and cathodoluminescence, and various methods to analyze chemical film structure and stoichiometry. The electronic bandgap of ZnO at about 3.3 eV was shifted up to 0.6 eV by isoelectronic mixing with Mg, or Cd. The natural n-type conductivity of the ZnO films was controlled across 6 orders of magnitude by variation of doping and oxygen background pressure. First results are presented about attempts to deposit p-type conducting ZnO films by codoping with activated N.