▎ 摘　　要

A portion of the electromagnetic wave spectrum between similar to 0.1 and similar to 10 terahertz (THz) suffers from the lack of powerful, effective, easy-to-use, and inexpensive emitters, detectors, and mixers. We propose a multilayer graphene-boron-nitride heterostructure which is able to emit radiation in the frequency range similar to 0.1-30 THz with the power density up to similar to 0.5 W/cm(2) at room temperature. The proposed device is extremely thin, light, flexible, almost invisible, and may become an important member of the family of devices operating at terahertz frequencies. DOI: 10.1103/PhysRevB.87.115405