Secondary Electron Emission from Germanium

Abstract

Secondary emission by electron bombardment has been measured for single crystals of Ge with $p\ensuremath{-}n$ junctions. Maximum yield was found in the range $\ensuremath{\delta}=1.15\ifmmode\pm\else\textpm\fi{}0.03$, at ${V}_{p}\ensuremath{\approx}500$ volts and room temperature. Increasing temperature decreased the yield because of a small interaction between the internal secondaries and the lattice. The most probable energy of emission was 1-2 ev. There was no change in yield with donor or acceptor concentration up to ${10}^{19}$/${\mathrm{cm}}^{3}$, and in particular there was no detectable effect of the space-charge fields under the surface. These results form the basis for discussion of the secondary emission process in semiconductors as compared with metals and insulators.