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FIZIKA A 13 (2004) 3 , 89-104
 
ELECTRON AND HOLE IMPACT IONIZATION COEFFICIENTS IN VERY HIGH FIELDS IN
SEMICONDUCTORS
F. M. ABOU EL-ELA and I. M. HAMADA
aDepartment of Physics, Faculty of Girls, Ain Shams University, Heliopolis,
Cairo, Egypt
bDepartment of Physics, Faculty of Science, Tanta University, Tanta, Egypt
Received 22 January 2004; revised manuscript
received 8 September 2004
Accepted 13 September 2004 Online 7 February 2005
We have fitted the soft lucky drift model of impact ionization of Ridley to
experimental data for GaAs, InP, Si, Ge and In0.47Ga0.53As
semiconductors. Excellent fits of the theory to experimental data were obtained by using
least-squares fitting algorithm. A generalized Keldysh formula has been used to introduce
a soft threshold factor. Generalized Keldysh formula originates from realistic energy
bands in semiconductors at high electric field which reflects the density of states of
energy bands. Keldysh factor and a new mean free path are calculated. A comparison with
reported values of both Ridley and Marsland showed reasonable agreement for mean free
path, but there are still large differences among Keldysh factors.
PACS numbers: 79.20Fv, 72.20Ht, 85.60.Dw
UDC 535.243.2, 535.427
Keywords: semiconductors, impact ionization, high field transport, GaAs, InP, Ge, Si,
In0.47Ga0.53As
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