(color online) Raman study of thermoelectricity in 2D materials. (a) Schematic for the heat conduction process in suspended few-layer MoS₂. (b) Raman spectra of suspended few-layer MoS₂ at different temperatures (left). The A_1g and E 2g 1 peak positions as functions of temperature (right). Both modes redshift as the temperature increases. (c) FWHM of the A_1g peak as a function of temperature. The FWHM increases as the temperature increases. (d) The A_1g mode frequency as a function of laser power. Redshifts are found as the temperature increases. Reproduced with permission from Ref. [119]. Copyright 2013, American Chemical Society.