Current Carrier Mobility Ratio in Semiconductors

Abstract

The ratio of the electronic mobility to the hole mobility in germanium has been reported by many workers. The ratio reported is usually obtained by measurements on two different samples of different conductivity types. The method suggested here deduces the mobility ratio from resistivity measurements made on a single sample. An accurate plot of resistivity as a function of temperature is made. The extrinsic and intrinsic branches of this curve are extrapolated to their intersection. If $r$ is defined as the ratio of the resistivity of this intersection point to the measured resistivity at the same temperature, the quantity [$\frac{1}{(r\ensuremath{-}1)}\ensuremath{-}r$] gives the mobility ratio for $P$ type samples, and its reciprocal for $N$ type samples.