Absorption, structural, and electrical properties of Ge films prepared by ion-beam-assisted deposition.

Effects of ion energy on the optical, microstructure, and electrical properties of Ge films prepared by ion-beam-assisted deposition were investigated. The absorption edge is found to shift toward a longer wavelength when the ion energy increases. 150 eV ion bombardment energy could help to reduce absorption in the infrared spectrum, elevating 2% of film transmittance. Diffraction intensity decreases with bombardment ion energy indicates that the crystallinity of Ge film is degenerated. Electrical property has been analyzed through Hall measurement. The resistivity of sample prepared with 300 eV ion energy drops substantially from 477 to 137 Ω cm, and it changes slowly with further increase of ion bombardment energy.