Disordered materials with new optical properties are capturing the interest of the scientific community due to the observation of innovative phenomena. We present the realization of novel optical materials obtained by fractal arrays of silicon nanowires (NWs) synthesized at low cost, without mask or lithography processes and decorated with Er: Y 2 O 3, one of the most promising material for the integration of erbium in photonics. The investigated structural properties of the fractal Er: Y 2 O 3/NWs demonstrate that the fractal morphology can be tuned as a function of the sputtering deposition angle (from 5 to 15) of the Er: Y 2 O 3 layer. We demonstrate that by this novel approach, it is possible to simply change the Er emission intensity by controlling the fractal morphology. Indeed, we achieved the increment of Er emission at 560 nm, opening new perspectives on the control and enhancement of the optical response of …