Silicon NPN Transistor: Calculating Fermi-Level & Equilibrium Concentrations

[Mr_klein]

Homework Statement

we look at a silicum n++ p+ n transistor. given:

N_E= 1,0×10¹⁸ cm^–3;

N_B= 2,0×10¹⁶ cm^–3;

N_C = 2,0×10¹⁵ cm^–3;

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

Homework Equations

a. calculate the distance in eV from the fermi-level to E_Fi 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

The Attempt at a Solution

I don't really understand this yet, I've tried looking in my books and online but i don't understand what the N stands for. i found something like a doping concentration. and that Efi is the intrinstic fermi level but i don't know how to answer the questions. can someone please help. or at least point me to something i could read that would help.
thanks

 

[mfb]

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. Homework Equations ").