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The thermal equilibrium value of the majority carrier n n -bar and the thermal equilibrium value of the minority carrier p n -bar are calculated from the following set of equations:

By re-arranging the above two equations we get the following equation:

In second last equation we see that majority carriers consist two terms: first term is electrons contributed by ionization of the N D dopent atoms/cc and the second term is the electrons contributed through thermal generation of EHP. But since electrons contributed by EHP thermal generation is negligible compared to N D dopent atoms/cc as seen below so without any loss of accuracy we can use the last equation above.

In case of Silicon, doping is in the range from 10 12 Dopent Atoms/cc to 10 18 Atoms/cc.

Hence the thermal equilibrium value of the majority carrier in N-Type Si will range from n n -bar=10 12 electrons /cc to 10 18 electrons/cc.

The thermal equilibrium value of the minority carier in N-Type will range from p n -bar=10 8 holes /cc to 10 2 holes/cc. assuming n i =10 10 /cc.

2.2.5.1. The Energy-Band Diagram of N-Type and P-Type Semiconductor.

Left hand side diagram in Figure 2.2.28 is that of N-Type Material. The dopent N D donor atoms/cc introduce filled energy level E D very close to the lower edge (E C ) of the Conduction band.At room temperature the thermal energy is of the order of 25meV whereas 10meV is required to jump to the conduction band hence at Room Temperature all the donor atoms easily get positively ionized contributing their 5 th valence electrons to the conduction band. There are few and far between thermal generation of EHP also as indicated by EE’.

Right hand side diagram in Figure 2.2.28 is that of P-Type Material. The dopent N A acceptor atoms/cc introduce empty energy level E A very close to the upper edge (E V ) of the Valence band.At room temperature the thermal energy is of the order of 25meV whereas 10meV is required to jump to the empty energy level E A hence at Room Temperature all the acceptor atoms easily get negatively ionized by accepting the valence electron from the neighbouring Si-Atom thereby completing its octave and contributing equal number of vacancies in the Valence Band. These vacanicies wander about the Si-lattice as conducting positive carriers which we call holes. There are few and far between thermal generation of EHP also as indicated by EE’.

Comparing these two diagrams it is clear that holes will wander about the Si-lattice in much more sluggish manner as compared to conducting electrons. This has implications for its mobility.

2.2.5.2. Compensation in Semiconductors.

If both donor N d dopent/cc and acceptor N a dopent/cc are introduced simultaneously then the two compensate. The fifth electron from the donor atom goes to fulfil the octave of the acceptor atom. The Acceptor need not make its pick of the 4 th electron from the valence band. Thus equal number of donor and acceptor will compensate each other.Whatever is leftover decides the Type of the semiconductor.

If donor N d dopent/cc<acceptor N a dopent/cc then we have P-Type Si with net doping density = N a - N d =N A .

If donor N d dopent/cc = acceptor N a dopent/cc then we have Intrinsic Si with net doping density = N a - N d = 0 .

If donor N d dopent/cc>acceptor N a dopent/cc then we have N-Type Si with net doping density = N d - N a =N D .

Questions & Answers

I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
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LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
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How can I make nanorobot?
Lily
how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:  OpenStax, Solid state physics and devices-the harbinger of third wave of civilization. OpenStax CNX. Sep 15, 2014 Download for free at http://legacy.cnx.org/content/col11170/1.89
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