The effects of residual gases on optical constants of Al films

Using the attenuated total reflection technique, the effects of residual gases on optical constants of Al films have been investigated in situ during and after growth of films. It has been found that the optical constants of Al films are strongly affected by residual gases even under ultrahigh vacua (UHV) in the order of 10⁻⁶ Pa. In order to explore the origin of a variation in optical constants produced by the residual gases, the optical constants of Al films exposed to oxygen, nitrogen or hydrogen gases have been measured.