The on-chip terahertz spectroscopy and theoretical analysis of the work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under contract number DE-AC02-05CH11231 within the vdW heterostructure Program . The device fabrication is supported by the Army Research Office award W911NF2110176. S.C. acknowledges support from Kavli ENSI Heising-Simons Junior Fellowship. K.W. and T.T.
Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USAKavli Energy NanoScience Institute, University of California at Berkeley, Berkeley, CA, USASudi Chen, Alex Zettl & Feng WangKenji Watanabe International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, JapanMaterials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA