Electrical properties of diluted $n$- and $p$-Si$_{1-x}$Ge$_x$ at small $x$

Hall effect and conductivity measurements are taken on Si$_{1-x}$Ge$_x$ of $n$- and $p$-type at $x\le$ 0.05. Much attention is given to electrical measurements over a temperature interval of 25 to 40 K where the mobility of charged carriers is strongly affected by alloy scattering. The partial mobility of electrons and holes due to this scattering mechanism is estimated for $n$-Si$_{1-x}$Ge$_x$ and $p$-Si$_{1-x}$Ge$_x$ at small $x$. Together with this, an effect of the presence of Ge atoms upon the ionization energy of phosphorus and boron impurities is investigated. Some points related to an inhomogeneous distribution of Ge atoms in Si$_{1-x}$Ge$_x$ are discussed.