Photoinduced Heating of Graphitized Nanodiamonds Monitored by the Raman Diamond Peak

Abstract

Raman scattering investigations of the diamond peak properties of nanodiamonds with a size of 25 nm were performed in terms of temperature and laser power dependency. A similar trend of a bathochromic shift with increasing temperature and laser power was found, indicating the optical induced heating mechanism to be one of the main influencing factors on the Raman scattering behavior of nanodiamonds. As a direct consequence, nanodiamond particle impurities such as graphite have an indirect influence on the diamond peak properties by means of enhanced optical absorption of the particle, resulting in a higher rate of photoinduced heating. The results presented here are not only supplementing the list of influencing factors on the Raman scattering properties of nanodiamonds, but they also demonstrate that even a low graphite content leads to local particle temperature differences in the range of hundreds of °C already at low laser intensities within the range 105 W/cm2 with a substantial effect on the Raman s...