Thin films of different thicknesses in the range 400–1600 A˚ have been vacuum deposited on clean glass substrates held at room temperature by very fast evaporation of the Se10Sb10Te80bulk alloy. The thermoelectric power of these films has been measured as a function of temperature during heating and cooling cycles by the integral method. It is found that the thermoelectric power of these films is slightly different during the heating and the cooling cycles which is ascribed to slight reorientation of microcrystallites as also evidenced by x‐ray diffraction. It is further found that the thermoelectric power (at a constant temperature) is a function of film thickness; it varies nearly linearly with reciprocal thickness. From these data, the nature of carrier scattering in the films has been ascertained. From the energy‐dispersive x‐ray analysis patterns of the films the semiquantitative content of the constituent elements Sb, Se, and Te has been determined. ©1995 American Institute of Physics.