1512 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1953 



by the optical modes. Data on n-type germanium at 20 degrees K show a 

 range over which impurity scattering decreases and the mobihty increases 

 with field until lattice scattering dominates as at the higher temperatures. 



Shockley, W., see J. D. Eshelby. 



Shockley, W.^ AND R. C. Prim^ 



Space-Charge Limited Emission in Semi-Conductors, Phys. Rev., 

 90, pp. 753-758, June 1, 1953. 



A situation analogous to thermionic emission into vacuum can occur in semi- 

 conductors. A semi-conductor analog for a plane parallel vacuum diode may 

 consist of two layers of n type semi-conductor bounding a plane parallel slab 

 of pure semi-conductor. The current density analogous to Child's law is 

 J = O^eo^F^/STF^, where k = dielectric constant, eo = mks permittivity, n 

 = mobility, V = applied voltage, and W = thickness of pure region. The 

 condition prevailing at the space-charge maximum is analyzed taking into 

 account diffusion due to random thermal motion. Brief discussions are given 

 of the effect of fixed space charge, the dependence of mobilit}^ upon electric 

 field strength and the role of space-charge limited emission in a new class of 

 unipolar transistors. 



Slichter, W. p.' and E. D. Kolb' 



Solute Distribution in Germanium Crystals, Letter to the Editor, 

 Phys. Rev., 90, pp. 987-988, June 1, 1953. 



Townsend, J. R.^ 



A Dynamic Program for Conversion, Metal Progress, 63, pp. 79-81, 

 June, 1953. 



Turner, E. H.' 



New Non-Reciprocal Waveguide Medium Using Ferrites, Letter to 

 the Editor, I.R.E., Proc, 41, p. 937, July, 1953. 



Wannier, G. H.' 



Threshold Law for Single Ionization of Atoms or Ions by Electrons, 

 Phys. Rev., 90, pp. 817-825, June 1, 1953. 



When an electron hits an atom or ion, it may knock off an electron. This 

 process is fundamental in almost all types of gas discharge. The reaction is 

 endothermic; hence there is a threshold value in the electron energy below 



Bell Telephone Laboratories, Inc. 



