Fermi dirac level, Electrical Engineering

Assignment Help:

Fermi Dirac level:

Sol. The Fermi level is simply a reference energy level. It is the energy level at which the probability of finding an electron n energy unit above it in the conduction band is equal to the probability of finding a hole n energy units below it in the valence band. Very simply, it can be considered to the average energy level of the electrons, as illustrated in fig. (a). For simplification let us assume that (i) widths of energy bands are  small in comparison to forbidden energy gap between them (ii) all levels in a band have the same energy, bandwidths being assumed to be small (iii) energies of all levels in valence band are E0, as shown in fig. (a) and (iv) energies of all levels in conduction band are EG. Let the zero energy reference level be taken arbitrarily at the top of the valence band, as shown in fig. (b). Now number of electrons in conduction band, where P represents the probability of an electron having energy EG. Its value may be determined from Fermi Dirac probability distribution function given as where P (E) is the probability of finding an electron having any particular value of energy E.


Related Discussions:- Fermi dirac level

Eeprom, advantages and disadvantages

advantages and disadvantages

Physics, find the resultant of two forces 20N and25N acting at an angle 60...

find the resultant of two forces 20N and25N acting at an angle 60 degree each other

Design mux, Design 8:1 Mux for a given function, f=Σ (0, 1,5,7,9, 13)

Design 8:1 Mux for a given function, f=Σ (0, 1,5,7,9, 13)

Calculate the rms voltage generated in each phase, Q. Consider an elementar...

Q. Consider an elementary three-phase, four-pole alternator with a wye-connected armature winding, consisting of full-pitch concentrated coils.  Each phase coil has three turns,

Compound motor , Compound motor It is possible to arrange for part of...

Compound motor It is possible to arrange for part of the field  coil to be in series with the armature and part in parallel   This gives rise to a motor with a mix

Single phase half wave controlled rectifier , Single Phase Half wave contro...

Single Phase Half wave controlled Rectifier In half  wave  rectification either  the positive or negative half  of the ac wave is  passed while  the other  half is blocked. Be

#emf., what is the effect of back emf ?

what is the effect of back emf ?

Testing for continuity-earthing, Testing for Continuity : You may have obs...

Testing for Continuity : You may have observed sometimes that when all the connections in the appliance as well as the plug are made properly the appliance may still not work. Thi

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd