Thermal hysteresis during phase transition in Ag2Te thin films: Thickness effect

摘要

Electrical conductivity and thermoelectric power measurements as a function of temperature have been carried out on Ag2Te thin films of different thicknesses prepared on glass substrates at room temperature in a vacuum of 5times;10minus;5Torr. It is found that the phase transition temperatures (located by a steep change in resistance and thermoelectric power with temperature) during heating and cooling are different, thereby showing a thermal hysteresis during the phase transition. It is also found that the magnitude of the hysteresis is a function of thickness, increasing with decreasing thickness. This can be due to the large surfacehyphen;tohyphen;volume ratio, small grain size, and a large density of dislocations in thin films.