Seebeck effect of nano-scale p-type silicon films above room temperature

摘要

Nano-scale Al-doped silicon films are prepared by magnetron sputtering. The amount of Al doped in the films is controlled by regulating the Al sputtering power and duration. With appropriate amount of Al, the Seebeck coefficient of the Si films at room temperature is larger than 168 μV/K, which increases with temperature in agreement with the conventional theory for three-dimensional semiconductors. By reducing the Al sputtering time, however, step-like Seebeck coefficient versus temperature is observed. This anomalous behavior is explained by the step-like density of states for two-dimensional semiconductors.