School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK.
Adv Mater. 2017 May;29(19). doi: 10.1002/adma.201606372. Epub 2017 Mar 15.
The gate-tunable wide-band absorption of graphene makes it suitable for light modulation from terahertz to visible light. The realization of graphene-based modulators, however, faces challenges connected with graphene's low absorption and the high electric fields necessary to change graphene's optical conductivity. Here, a solid-state supercapacitor effect with the high-k dielectric hafnium oxide is demonstrated that allows modulation from the near-infrared to shorter wavelengths close to the visible spectrum with remarkably low voltages (≈3 V). The electroabsorption modulators are based on a Fabry-Perot-resonator geometry that allows modulation depths over 30% for free-space beams.
石墨烯的栅极可调宽带吸收使其适合从太赫兹到可见光的光调制。然而，基于石墨烯的调制器的实现面临着与石墨烯的低吸收率以及改变石墨烯的光学电导率所需的高电场相关的挑战。在这里，展示了具有高介电常数氧化铪的固态超级电容器效应，该效应允许用近红外光到更短的接近可见光光谱的波长进行调制，且所需电压非常低（≈3 V）。电光吸收调制器基于法布里-珀罗谐振腔几何结构，允许自由空间光束的调制深度超过 30%。
