Ultrathin metal are of a high interest due to their unique properties. Due to small thickness of nanometre scale they stay semi-transparent in a wide wavelength range. They are used in many field, for example, optoelectronics, optics, engineering, electronics, decoration and plasmonic. Chromium (Cr) metal thin films are attractive due to their mechanical, electrical and optical properties. Cr films play an essential role in many applications and can be used as decorative plating, transparent electrode, spacer layer, adhesive layer, light absorbing layer, optical beam splitters, spatial light modulator and tunable filter.
In our research, we have made a detailed study of Cr ultrathin films. Films with various thickness were deposited using magnetron sputtering. The films were investigated by various techniques in order to get better understanding of observed dependencies. A film thickness was varied from several nanometers to several tens of nanometrs. Such coatings, for example, might be used in optoelectronics and plasmonics.
It was evaluated that films have only chromium cubic phase. The elemental composition analysis confirmed the purity of the films.
Sheet resistance significantly decreased with the film thickness increased from 3 nm (1000 Ω/sq) to 12 nm (55 Ω/sq), afterward, with further thickness increase up to 57nm sheet resistance decreased to 19 Ω/sq. These values are comparable with the ITO values.
Optical constants of ultrathin Cr films were evaluated from ellipsometry are and compared with spectrophotomic measurements. These constants might be used for further modeling of multilayer coatings.