Quantum Dots in semiconductor doped glasses are of great significance because of their applications in opto-electronic devices. The advancement in this area has been hampered by the reversible and irreversible photo-darkening effects, which come into picture during laser irradiation of these nanocrystals. Photo-darkening is a photo-chemical process and involves deposition of ions on the existing quantum dots. This apparent increase in the size of the quantum dots leads to reduction in non-linear optical properties, which limits the applications of nanocrystals towards opto-electronic devices. This process involves movement of the ions from the surrounding matrix to the surface of the nano-particles thereby increasing the size of quantum dots. It is therefore important to study the temperature profiles of the particles/glass matrix interface during and after laser irradiation. It is found that bigger particles can reach higher temperatures compared to smaller particles since the surface to volume ratio of smaller particles is higher and hence heat dissipated to the surrounding matrix is faster. Also the temperature rise in the initial stages is much higher compared to later stages of pulse irradiation. In the present work, it is assumed that the diffusion length is less than the half of the distance between the nearest neighbor particles. The knowledge of temperature profiles will throw light on the mechanism of movement of the surrounding ions. This may help in overcoming the photo-darkening effect.
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