[Chimie]

Bonjour!
Result of Silicon crystal analyzation shown that there is an amount of arsenic As atoms in silicon crystal at Concentrate percentage which is 0.0002%. Assuming if conductivity concentration which promote by heat is an eliminated amount.
Find out the electrical conducting density?
Where Molarity of silicon = 12.1cm3/mole.
Answer:
We get N-type semiconductor
Density= w/v....(1)
V= Moles#/Molarity....(2)

1/Calculation of moles number:
Moles#=w/M.wt....(3)
= .0002*100/28.1
=7.117*10^-4 mole

2/ Calculation of volume:
back to equation #2
V=7.117*10^-4/12.1
=5.88*10-5 cm3

3/W of Si =moles#/atomic mass
= 7.117*10^-4/28.086
= 2.534*10^-5gm

Back to density
D = 2.534*10^-5/5.88*10^-5
= 0.4309 gm/cm3
 
Question:
where could the previous answer take me to?
Question:
Dose electrical conducting density try to tell me something about which of charge conductive (holes or electrons) have majority on other?
Information:
I'm already know that it's N-type SC which means the charge conductive is electron.
Question:
Did I need to find the electron numbers?

I need a diagram of conducting band,valance band and energy gap between them.

Come on chmists do something about it.