Hello,

Question

((((((I need the answer in a hour from my posting)))))
I have been posting this problme for four days ago, so please show Sympathy.
I solved it but I want to be 100% su ...there is moreshow problem
Hello,

((((((I need the answer in a hour from my posting)))))
I have been posting this problme for four days ago, so please show Sympathy.
I solved it but I want to be 100% sure to go on.

The 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
my humble ideas goes like,
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

If I do it in appropriate way why I couldn't find the Weight in grams of Si. Hold on, silicon is the conductive and arsenic is a blotch which give us a N-type conducting. Avoiding the weight of Si we can go throw this rule which says: Density =the number of conductive * 1 cm3
Where 1 cm3 = 1mole =Avogadro’s number
1 mole = 6.022 x 10^23 atoms
Now, how could I figure out the number of conductive?
How can I solve this, Am I doing well ?!

Draw the diagram of band and name the form of boundary

Finding out the Si weight
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
= 0.4309gm/cm3
Another solution
segma= 1/D
Log segma = 4.247 –(92924/T)
=2.7221998*10^-6 ms
D = 367.349*10^3

I really need help.
Electrical conductivity or specific conductance

is a measure of a material's ability to conduct an electric current. When an electrical potential difference is placed across a conductor, its movable charges flow, giving rise to an electric current. The conductivity s is defined as the ratio of the current density J to the electric field strength E

J=sE

where electrical conductivity s is has been calculated
means it can be found in table as a constant.

!!!!!!!!!
Any Ideas!

will I have an answer any time soon?!
please respond

Answer 1

Your question(s) and answer(s)(?) are so disorganized that I can't make heads or tails of the question(s), much less how you propose to solve it(them).

Answer 2

Thanks dr Bob for your reply.
Here's the organized version
Question:
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 conductivity density try to tell me something about which of charge transfers (holes or electrons) have majority on other?
Information:
I'm already know that it's N-type SC which means the charge transfer is electron.
Question:
Did I need to find the electron numbers?