Photoinduced Change of Thermophysical Properties of Chalcogenide As₂S₃Thin Films

Author： Kim S. Kang C. Hahn S. Lee S. Kim J.

ISSN： 0195-928X

Source： International Journal of Thermophysics, Vol.25, Iss.6, 2004-11, pp. : 1871-1879

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Abstract

The reversible photoinduced change exhibited by amorphous chalcogenide glasses has been extensively studied recently, partly as an interesting subject for fundamental research in the field of disordered solids and partly due to potential applications in optoelectronics such as photoresists, optical memories, optoelectronic circuits, etc. The illumination of many amorphous chalcogenides changes their internal and/or surface structure while preserving their amorphous state. In this study, amorphous arsenic trisulfide (As₂S₃) thin film samples whose thickness is 5 µm were prepared on silicon wafers by thermal evaporation, and their thermal diffusivity and thermal conductivity were measured by photoacoustic spectroscopy and a 3? method, respectively. These measurements were repeated after illumination by an Ar⁺ laser beam whose photon energy E_g is consistent with the energy band gap of As₂S₃. The results show that the thermal diffusivity and thermal conductivity increase by about 50% and 14–15%, respectively, by the photoinduced darkening, and this can be explained by the rearrangement of atoms and thermal expansion of the film.