Pulsed laser deposition of highly conductive ZnO films

Zinc oxide (ZnO) is considered as an important compound for optically transparent and electrically conductive layers. Its importance has been increasing in recent years mainly in large area photovoltaic applications. Since commercially used ITO (Indium Tin Oxide) suffers from expensive Indium and related health risks, ZnO can serve 22 as its cheaper alternative. However, pure, undoped ZnO is rather poor electrical conductor (in orders of 10^-1 – 10⁰ Ω.cm) proper doping is inevitable. Al and Ga are considered as the most promising doping elements, but on the other hand, deposition conditions are also very important factor for achieving of high conductivity of ZnO films. The contribution deals with pulsed laser deposition (PLD) of doped ZnO films where different levels of Al or Ga was used. Along with the doping concentration, the deposition rate was investigated as the most influential deposition parameter. Experimental samples were analysed by Hall measurements and results achieved under optimised growth conditions exhibited resistivity in order to 10^-4 Ω.cm. (author)