Secondary Electron Emission from Germanium

Secondary emission by electron bombardment has been measured for single crystals of Ge with $p-n$ junctions. Maximum yield was found in the range $\delta =1.15\mathrm{}\pm 0.03$, at $V_p\approx 500$ 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.