Monday, June 29, 2015
Abstract-Strong emission of terahertz radiation from nanostructured Ge surfaces
Indirect band gap semiconductors are not efficient emitters of Here, we report strong emission of from wafers with nanostructured The amplitude of from an array of nano-bullets (nano-cones) is more than five (three) times larger than that from a bare-Ge wafer. The power of the from a wafer with an array of nano-bullets is comparable to that from n-GaAs wafers, which have been widely used as a terahertz source. We find that the from wafers with the nano-bullets is even more powerful than that from n-GaAs for frequencies below 0.6 THz. Our results suggest that introducing properly designed on indirect band gap semiconductor wafers is a simple and cheap method to improve the efficiency of the wafers significantly.