A semiconductor has equal electron and hole concentration of `6xx10^(8)//m^(3)`. On doping with certain impurity, electron concentration increases to `9xx10^(12)//m^(3)`. (i) Identify the new semiconductor obtained after doping. (ii) Calculate the new hole concentration. (iii) How does the energy gap vary with doping?A. `2xx10^4` per `m^3`B. `2xx10^2` per `m^3`C. `4xx10^4` per `m^3`D. `4xx10^2` per `m^3`

A semiconductor has equal electron and hole concentration of `6xx10^(8

1.	A semiconductor has equal electron and hole concentration of `6xx10^(8)//m^(3)`. On doping with certain impurity, electron concentration increases to `9xx10^(12)//m^(3)`. (i) Identify the new semiconductor obtained after doping. (ii) Calculate the new hole concentration. (iii) How does the energy gap vary with doping?A. `2xx10^4` per `m^3`B. `2xx10^2` per `m^3`C. `4xx10^4` per `m^3`D. `4xx10^2` per `m^3`
Answer» Correct Answer - C As, `n_e n_h=n_i^2` Here, `n_i=6xx10^8 per m^3 and n_e = 9xx10^12 per m^3` `therefore n_h=n_i/n_e=((6xx10^8)^2)/(9xx10^12)=4xx10^4 per m^3`

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