ECE340_L14_S14_Distribution

# Quasi fermi energy or quasi fermi level quasi fermi

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Unformatted text preview: recombina_on rate When the light is turned oﬀ, the genera_on rate drops back to the thermal genera_on rate but the recombina_on rate remains propor_onal to the product of the electron and hole concentra_ons. This is deﬁned as _me = 0. dp(t ) dn(t ) d [ no + δ n(t )] dδ n(t ) = = = = go (T ) − r (t , T ) dt dt dt dt = α r no po − α r ⎡( no + δ n(t )) ( po + δ p(t )) ⎤ ⎣ ⎦ gtot (t = 0, T ) = go (T ) r (t , T ) = α r ⎡( no + δ n(t )) ( po + δ p(t )) ⎤ ⎣ ⎦ = −α r ⎡( no + po )δ n(t ) + δ n 2 (t ) ⎤ ⎣ ⎦ NOTE: For Band-Band Recombination Where δ n(t ) = δ p(t ) 22 Example: Recombina_on in GaAs •  Note: The assump_ons po&gt;&gt;no and po&gt;&gt;δn are valid A GaAs sample N a = 1015 cm −3 = po ni2 (10 6 cm −3 )2 no = = = 10 −3 cm −3 po 1015 cm −3 − tτ n −t δ n(t ) = Δne = 10 e n(t ) = no + δ n(t ) = δ n(t ) 14 δ p(t ) = δ n(t ) = 10 e p(t ) = po + δ p(t ) 14 −3 −t p(t ) = 10 cm + 10 e 15 14 10 −8 10 −8 −t cm −3 cm −3 10 −8 cm −3 Other G- R Processes Impact Ioniza2on http://www.iue.tuwien.ac.at/phd/entner/node11.html Auger, SRH GR http://ecee.colorado.edu/~bart/ecen5355/newbook/chapter2/recomb.htm 24 G- R Through Trapping Centers Genera2on- Recombina2on Traps in Silicon ༉ ༉ Empty State ༉ ༉ ༉ ༉ ༉ 25 Steady Illumina_on: Revisited...
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