Weis, P.P.WeisGarcia-Pomar, J.L.J.L.Garcia-PomarHoh, M.M.HohReinhard, B.B.ReinhardBrodyanski, A.A.BrodyanskiRahm, M.M.Rahm2022-03-042022-03-042012https://publica.fraunhofer.de/handle/publica/23014010.1021/nn303392sNew applications in the realms of terahertz (THz) technology require versatile adaptive optics and powerful modulation techniques. Semiconductors have proven to provide fast all-optical terahertz wave modulation over a wide frequency band. We show that the attenuation and modulation depth in optically driven silicon modulators can be significantly enhanced by deposition of graphene on silicon (GOS). We observed a wide-band tunability of the THz transmission in a frequency range from 0.2 to 2 THz and a maximum modulation depth of 99%. The maximum difference between the transmission through silicon and GOS is Delta t = 0.18 at a low phor doping power of 40 mW. At higher modulation power, the enhancement decreased due to charge carrier saturation. We developed a semianalytical band structure model of the graphene silicon interface to describe the observed attenuation and modulation depth in GOS.en621540journal article