Research / 2020 / Article / Fig 2

Review Article

Optical Patterning of Two-Dimensional Materials

Figure 2

Laser-induced doping and phase transition of 2D materials. (a) Schematic of laser-induced doping of phosphorous into MoS2 with phosphine gas. (b) PL mapping of MoS2 shows enhanced PL intensity in the phosphorous-doped region. (c) Time-resolved PL spectra show that the sample with laser-induced doping (left) exhibits the higher stability than the sample with laser annealing (right). Reproduced from Ref. [52] with permission from Wiley, copyright 2015. (d) Schematic of laser-induced phase transition of MoTe2 from 2H phase to 1T phase. (e) Optical images of 2H phase and 1T phase of MoTe2 before and after laser scanning. (f) Relative binding energy per unit formula for 2H and 1T phases as a function of Te vacancy concentration. Inset shows a STEM image of Te vacancy after laser scanning. Scale bar: 3 Å. Reproduced from Ref. [56] with permission from the American Association for the Advancement of Science, copyright 2015. (g) Schematic and mechanism of hot electron-mediated 2H to 1T phase transition in MoS2. (h) Raman spectra of MoS2 with and without Au nanoparticles showing signature peaks of 1T phase in the presence of Au nanoparticles under laser illumination. Reproduced from Ref. [58] with permission from Wiley, copyright 2014.