Piece of doped silicon has hole concentration of p=10^17/cm^3. Knowing that the
ID: 1925015 • Letter: P
Question
Piece of doped silicon has hole concentration of p=10^17/cm^3. Knowing that the impurities in the semiconductor are all the same type, operating at room temp.a) find concentration of free electrons, n? np=ni^2
I believe this answer is 1000 electrons/cm^3
b) find concentration of impurities N, introduced? this is the one I'm not sure about I think it is the 10^17/cm^3
c) What kind of impurities has been introduced, (donors or acceptors) and explain why. I think it is acceptors due to p-type so there are more holes than electrons. Any help will be appreciated
Explanation / Answer
a. np = ni^2 , ni is approximately 10^10 / cm^3. for a P type material, p = 10^17 n = 10^3 = 1000. you are correct. b. this is P type material, concentration of impurities introduced is 10^17. but they really shouldnt use the variable "N" here, because N suggests that its N type. c. its holes = p type materal = acceptors , cuz its missing 1 electron, therefore its + charge, and it can "accept" an additional electron from the donor. http://en.wikipedia.org/wiki/P-type_semiconductor