Fig. 1
From: Anisotropic Terahertz Emission from Bi2Se3 Thin Films with Inclined Crystal Planes
Terahertz (THz) emission results from bulk Bi2Te2Se and a schematic of THz generation mechanisms. a Time profile of the THz electric field emitted from Bi2Te2Se obtained with a variation of the sample azimuth Φ from 0° to 270°. The inset shows a schematic of the THz generation experiment. b Φ-dependence of maximum (filled circle) and minimum (open square) amplitudes indicated in (a). c, d THz generation mechanism by two surge current contributions, i.e., the photo-Dember effect and photocarrier acceleration by surface band bending, respectively. The horizontal axis means the depth d from the surface. The vertical axes in (c) and (d) indicate a lateral dimension in the sample and an electron energy E, respectively. e (h) represents electron (hole). E F and E C (E V) lines denote a Fermi energy and conduction band minimum (valence band maximum) of the bulk state