The term "'gain-switching "'derives from the fact that the optical gain is negative when carrier density or pump intensity in the active region of the device is below threshold, and switches to a positive value when carrier density or the pump intensity exceeds the lasing threshold.
42.
The term "'gain-switching "'derives from the fact that the optical gain is negative when carrier density or pump intensity in the active region of the device is below threshold, and switches to a positive value when carrier density or the pump intensity exceeds the lasing threshold.
43.
Even though one can understand the principal behavior of semiconductor absorption on the basis of the Elliott formula, detailed predictions of the exact E _ \ lambda, F _ \ lambda, and \ gamma _ \ lambda ( \ omega ) requires a full many-body computation already for moderate carrier densities.
44.
In which n _ q is the carrier density, and its steady state value is \ overline { i } \ equiv I = q \ mu n _ qEA, A being the device cross-section surface; furthermore, we use the same symbols for both the time averaged and the instantaneous quantities.
45.
The conventional " hole " current is in the negative direction of the electron current and the negative of the electrical charge which gives I _ x = ntw (-v _ x ) (-e ) where n is charge carrier density, tw is the cross-sectional area, and-e is the charge of each electron.
46.
Once the carrier density becomes too high ( e . g . due doping ), the energy of the system can be lowered by the localization of the formerly conducting electrons ( band width reduction ), leading to the formation of a band gap, e . g . by pressure ( i . e . a semiconductor / insulator ).
47.
As recombination takes hold, the minority carrier densities drop with depth to their equilibrium values for bulk minority carriers, a factor exp ( " " & phi; B " / " V th " ) smaller than their bulk densities " n B ", " p B " as majority carriers before injection.
48.
If you wanted to know when ( or if ) the actual silicon fails, I would imagine it would be quite happy as the temperature went down, the intrinsic resistivity would be going up and the carrier density would be going down, but silicon designers should be able to make heavily "'Sp in ni ng Spark "'22 : 36, 15 April 2008 ( UTC)
49.
To become hot and enter the conduction band of SiO 2, an electron must gain a kinetic energy of ~ 3.2 eV . For holes, the valence band offset in this case dictates they must have a kinetic energy of 4.6 eV . The term " hot electron " comes from the effective temperature term used when modelling carrier density ( i . e ., with a Fermi-Dirac function ) and does not refer to the bulk temperature of the semiconductor ( which can be physically cold, although the warmer it is, the higher the population of hot electrons it will contain all else being equal ).
