Fig. 2: Characterization of p-type doping and homogeneity of CVD-grown Nb-WS2.
From: Atomic Nb-doping of WS2 for high-performance synaptic transistors in neuromorphic computing
a Raman spectra of Nb-WS2, exhibiting peaks at 349 cm−1 and 416 cm−1. b PL spectra of Nb-WS2, revealing emission characteristics at approximately 630 nm. The emission wavelength of undoped WS2 is 626.9 nm, whereas the emission wavelengths of 2% and 5% Nb-doped WS2 redshifted by 3.7 nm and 10.6 nm, respectively. c Differential reflectivity of CVD Nb-WS2 flakes. The neutral exciton peak was observed at 630 nm. d-f Raman mapping graphs illustrating the high homogeneity of undoped WS2, 2% Nb-WS2, and 5% Nb-WS2. XPS spectra and curve fitting of g Nb, h W, and i S
