Photoelectrochemical study of thin anatase TiO2 films prepared by metallorganic chemical vapor deposition

Thin films of TiO2 have been prepared by metallorganic chemical vapor deposition. The resulting anatase films are highly resistive. By electrochemical doping, the donor density can easily be raised by two orders of magnitude, resulting in a conducting film. From optical and photocurrent measurements, an indirect bandgap of 3.26 eV is derived for polycrystalline anatase films. Electrolyte electroreflection reveals a direct optical transition of anatase at 3.8 eV. The anatase electrodes can be sensitized by zinc carboxyphenyl porphyrin.