Up

Recombination

binary_zb {
 name    = Si                    # material name, e.g. Si, GaAs, InP, ...

 ...

 recombination{
                                 # Shockley-Read-Hall recombination
   SRH{       tau_n  = 1.0e-9    # [s]-3  zero doping scattering time for electrons
              nref_n = 1.0e19    # [cm-3] reference doping concentration for electrons
              tau_p  = 1.0e-9    # [s]-3  zero doping scattering time for holes
              nref_p = 1.0e18    # [cm-3] reference doping concentration for holes
   }

   The generation/recombination process can be assisted by impurities.
   This is modeled by the Shockley-Read-Hall model (SRH).
   The recombination/generation rates depend on the deviation of the carrier concentration from the equilibrium value
   and the scattering rates depend on the doping concentration.

   R_SRH = ( n p - n_i² ) / ( ( tau_p ( n + n_i ) + (tau_n ( p + n_i ))

   tau_n(N_D+N_A) = tau_n / ( 1 + [ ( N_D+N_A ) / nref_n ] )
   tau_p(N_D+N_A) = tau_p / ( 1 + [ ( N_D+N_A ) / nref_p ] )


                                 # Auger recombination
   Auger{     c_n    = 2.8e-31   # [cm6/s]
              c_p    = 9.9e-31   # [cm6/s]
   }

   More information on the Physics: Auger recombination processes in semiconductor heterostructures

   For devices with an extremely high carrier concentration the Auger process is the dominant recombination channel.
   The process involves three particles and therefore scales with the third power of the carrier densities.

   The phonon-assisted Auger recombination rate, which plays an important role especially at high carrier injection,
   respectively high doping levels, will be modeled in the program by the following equation:

   R_Auger = ( c_n n  + c_p p ) ( np - n_i² )



                                 # direct recombination
   radiative{ c = = 2.0e-10 }    # [cm3/s]
                                 # 2.0e-10 for GaAs, 0 for Si (indirect semiconductor)

   The simplest process for the generation and recombination of electron-hole pairs is the direct process
   via the emission or absorption of a photon (radiative recombination). This is important for light emitting devices.

   R_radiative = c ( n p - n_i² )

 }

}