ZnO is a promising material for many different applica-
tions such as solar cells, gas sensors, ultrasonic oscillators
and transducers [ l-51. Its direct optical bandgap (3.3 eV)
is wide enough to transmit most of the useful solar radiation
in ZnO/CdS/CuInSe,-type solar cells. Moreover, ZnO is a
good candidate to substitute indium tin oxide (ITO) and tin
oxide ( SnOz) in conductive electrodes of amorphous silicon
solar cells due to the high stability of ZnO films in a hydrogen
plasma. In the present work ZnO thin films are prepared by
the spray pyrolysis method which is well known for its sim-
plicity, reproducibility and possibility to produce cheap large-
area films.