Fig. 4: Effects of wavelength, gate voltage and laser power on photocurrent decay lengths in Sb-doped Bi2Se3.
From: Millimetre-long transport of photogenerated carriers in topological insulators
The dashed lines indicate the contacts. The measurements are carried out at 7 K and zero source–drain and gate biases. a–c 2D photocurrent maps. d–f line cuts along the nanoribbons axis. a, d Gate voltage dependence. Inset, band diagrams showing EF position. Laser power is 166 nW. b, e Laser power dependence. c, f Wavelength dependence. Laser power from 77 to 280 nW was used for different wavelengths to maintain the same exciton injection rate. The scale bar denotes 30 μm.
