ゲルマニウム斜方向蒸着膜の異方性について

抄録

Germanium thin films obliquely deposited in vacuum have been found to be photoelectrically anisotropic, viz., when they are illuminated by light, a high photo-voltage appears on them along the direction of deposition. A further study is made on this anisotropy.
If the illumination is by a polarized light, the intensity of transmitted light rests with the orientation of electric vector of the incident light, which implies that the absorption coefficient of the film has different values in two directions, parallel and perpendicular to the direction of deposi-tion, with the result that the transmitted light becomes elliptically polarized when a plane-polarized light falls on the film. This is explained by self-shadowing that occurs during the oblique deposi-tion: the growing crystallites prevent the impinging atoms from reaching the substrate where the crystallites cast shadows leaving there undeposited areas. Hence, in forming a film, all the crys-tallites grow long, crosswise to the direction of deposition. A light in passing through such an obliquely deposited film of oriented long crystallites suffers the greatest absorption when the electric vector is parallel to the long axes of the crystallites. This is the reason why an obliquely deposited film shows anisotropy, which is ascertained by the obliquely deposited germanium film. During its deposition in vacuum, its electric conduction has been observed to be also anisotropic.