Question

A pure semiconductor has equal electron and hole concentration of 10¹⁶ m^-3. Doping by indium increases nh to 5 × 10²² m^-3. Then, the value of n_e in the doped semiconductor is ______.

Options

• 10⁶/m³

• 10²²/m³

• 2 × 10⁶/m³

• 2 × 10⁹/m³

Answer 1

A pure semiconductor has equal electron and hole concentration of 10¹⁶ m^-3. Doping by indium increases nh to 5 × 10²² m^-3. Then, the value of n_e in the doped semiconductor is 2 × 10⁹/m³.

Explanation:

Here, n_i = 10¹⁶ m^-3, n_h = 5 × 10²² m^-3

As n_en_h = `"n"_"i"^2`

∴ n_e = `"n"_"i"^2/"n"_"h"`

= `((10^16"m"^-3)^2)/(5xx10^22"m"^-3)`

= 2 × 10⁹m^-3