Measurement of Hot Carrier Diffusion Constant in Semiconductors

Measurements of the electric field dependence of the hole diffusion constant in n-type germanium were made up to 2000 V/cm at temperatures of 297°, 195°, and 77°K. A distinctive feature of our experiments was the attenuation-rate measurements of sinusoidally modulated hole wave drifting along a filamentary specimen by the electric field supplied from a high-voltage pulser. The resistivity of the specimen was 5.3 Ω· cm and the hole diffusion constant was obtained which increased nearly in proportion to the two-thirds power of the electric field above 50 V/cm at 297°K and increased more rapidly at lower temperatures. For example, the result was Dp=900 cm2/sec when the electric field intensity was 1000 V/cm at 297°K.