FLOW OF ELECTRONS AND HOLES IN GERMANIUM 607 



(T ^ conductivity of semiconductor. 



(To = normal conductivity of semiconductor, with no added carriers. 



2 = a/ao = M/Mn , reduced conductivity of semiconductor. 



/ = time variable. 



T = temperature in degrees absolute. 



T = mean lifetime for holes for small added concentrations, in an n- 



type or in an intrinsic semiconductor. 



r„ = mean lifetime for electrons (concentration-dependent). 



Tp = mean lifetime for holes (concentration-dependent). 



r,. = mean lifetime for holes, for small added concentrations in an n- 



type semiconductor, due to mass-action recombination alone, 



r = //r = reduced time variable, 



ir = eV/kT, reduced electrostatic potential. 



X = distance variable. 



.Y = x/Lp , reduced distance variable. 



V = electrostatic potential. 



