Black-body emission from nanostructured materials

Photoluminescence (PL) experiments on materials of low thermal conductance can cause black-body emission from the sample even at low intensities of laser excitation. This thermal emission may be misinterpreted in terms of quantum emission. Although the quantum origin of most radiative emissions in nanostructured materials such as porous silicon is well established, we show in this paper that SiC nanoparticles and mechanically milled Si do exhibit thermal emission at typical excitation intensities for PL measurements provided the samples are under vacuum. An Si membrane was also investigated and the fact that it did not emit black-body radiation is explained with a simple analysis of the heating in materials of reduced dimensionality.