BLACKBODY EMISSION UNDER LASER EXCITATION OF SILICON NANOPOWDER PRODUCED BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Previous results concerning radiative emission under laser irradiation of silicon nanopowder are reinterpreted in terms of thermal emission. A model is developed that considers the particles in the powder as in dependent, so under vacuum the only dissipation mechanism is thermal r adiation. The supralinear dependence observed between the intensity of the emitted radiation and laser power is predicted by the model, as i s the exponential quenching when the gas pressure around the sample in creases. The analysis allows us to determine the sample temperature. T he local heating of the sample has been assessed independently by the position of the transverse optical Raman mode. Finally, it is suggeste d that the photoluminescence observed in porous silicon and similar ma terials could, in some cases, be blackbody radiation. (C) 1998 America n Institute of Physics.