Investigation of heat transfer of bulk and thin-film PbInTe samples by the method of dynamic gratings

Abstract

Measurements of the thermal diff usivity of thin and bulk indium-doped lead telluride have been taken using a modifi ed method of dynamic gratings. Thermal gratings were recorded by a 20 ns pulsed laser radiation at a wave length of 532 nm. Dynamic gratings were recorded by a 635 nm continuous laser radiation. The analysis of the diff raction signal kinetics made it possible to determine the life-time of thermal gratings recorded in the investigated samples. It is shown that the use of an additional homodyne fi eld coherent with respect to the diff raction signal fi eld makes it possible to enhance and fi lter off the selected information component. Based on registered kinetic dependences of the diff racted signal intensity, the thermal diff usivity of bulk and thin fi lm indium-doped lead telluride samples was determined. It has been established that for a micron-thick fi lm, the thermal diff usivity is ten percent lower than for a bulk sample. An investigation has been made into the dependence of the heat transfer in the said samples on their temperature and it has been shown that the rise in the samples′ temperature in the range from 40 to 95 o C results in a 20-percent decrease of their thermal diff usivity.