Carbon possesses the unique property to get hybridized in two different forms: the sp(2) and the sp(3). Moreover, carbon easily bonds with hydrogen and other chemical elements to form carbon-based materials with different properties. Here, Er3+-doped amorphous hydrogenated carbon (a-C:H) films deposited via a mixed CVD magnetron sputtering process are studied. The deposition parameters are related to the physical and optical properties of the Er-doped carbon films. (C) 2004 Elsevier B.V. All rights reserved.