Yoo, Hyung Keun Yoon, Youngwoon Lee, Kiejin Kang, Chul Kee, Chul-Sik Hwang, In-Wook Lee, Joong Wook 2024-01-20T09:31:26Z 2024-01-20T09:31:26Z 2022-01-25 2014-07 0003-6951 https://pubs.kist.re.kr/handle/201004/126609 Using hybrid bilayer systems comprising a molecular organic semiconductor and silicon, we achieve optically controllable active terahertz (THz) modulators that exhibit extremely high modulation efficiencies. A modulation efficiency of 98% is achieved from thermally annealed C-60/silicon bilayers, due to the rapid photo-induced electron transfer from the excited states of the silicon onto the C-60 layer. Furthermore, we demonstrate the broadband modulation of THz waves. The cut-off condition of the system that is determined by the formation of efficient charge separation by the photo-excitation is highly variable, changing the system from insulating to metallic. The phenomenon enables an extremely high modulation bandwidth and rates of electromagnetic waves of interest. The realization of near-perfect modulation efficiency in THz frequencies opens up the possibilities of utilizing active modulators for THz spectroscopy and communications. (C) 2014 AIP Publishing LLC. English AMER INST PHYSICS Highly efficient terahertz wave modulators by photo-excitation of organics/silicon bilayers Article 10.1063/1.4887376 1 APPLIED PHYSICS LETTERS, v.105, no.1 APPLIED PHYSICS LETTERS 105 1 N scie scopus 000339664900015 2-s2.0-84908518376 Physics, Applied Physics Article TIME-DOMAIN SPECTROSCOPY THIN-FILM TRANSISTORS DOPED SILICON THZ METAMATERIALS TECHNOLOGY TRANSITION MOBILITY