Fig. 2: Electrical tunable Raman scattering spectra of BP. | Nature Communications

Fig. 2: Electrical tunable Raman scattering spectra of BP.

From: Ultra-sensitive polarization-resolved black phosphorus homojunction photodetector defined by ferroelectric domains

Fig. 2

a Schematic illustration of electrical tunable anisotropic Raman vibration modes in BP. The ferroelectric field enhances the Ag2 vibration under 0° polarization light. The 0° (90°) light is linearly polarized along AC (ZZ) direction. The green arrows represent the vibration directions of raman modes. The E represents the direction of ferroelectric field and the yellow spheres reprensent the p-type doping effect on BP by ferroelectric field. b Typical measured Raman spectrum of exfoliated BP flake. The insets illustrate three Raman vibration modes of BP. c Polarized Raman spectra of BP sample with different polarization angles (0°, 30°, 60°, 90°). d, e The measured (dots) and fitted (line) angular-resolved Raman intensity ratio of the Ag2/Ag1 mode and B2g/Ag1 mode. The solid lines are fitted using the function of I(Ag) = (acos2θ + csin2θ)2 and I(B2g) = e2sin22θ, where a, c, and e represent the magnitude of three independent components of Raman tensor, θ is the angle between the incident polarization and the AC direction.

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