Silicon npn transistor

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1. Apr 9, 2015

Mr_klein

1. The problem statement, all variables and given/known data
we look at a silicum n++ p+ n transistor. given:

NE= 1,0×1018 cm–3;

NB= 2,0×1016 cm–3;

NC = 2,0×1015 cm–3;

here E stands for the emitter, B for the basis and C for the collector

2. Relevant equations
a. calculate the distance in eV from the fermi-level to EFi for the emitter the base and the collector.
b. how large is the electron concentration at thermal equilibrium in the emitter, base and collectro
c. how large is the hole concentration at thermal equilivirum in the emitter, base and collector

3. The attempt at a solution
I dont really understand this yet, ive tried looking in my books and online but i dont understand what the N stands for. i found something like a doping concentration. and that Efi is the intrinstic fermi level but i dont know how to answer the questions. can someone please help. or at least point me to something i could read that would help.
thanks

2. Apr 9, 2015

Staff: Mentor

Those numbers are doping concentrations, yes.
Your book should have formulas how they relate to energy levels (that is the purpose of the section "2. Relevant equations").