NEET2011PhysicsSemiconductorsActual
Pure Si at 500 ~K has equal number of electron (n_e ) and hole (n_h ) concentrations of 1.5 10¹⁶ ~m ⁻³ . Doping by indium increases n_h to 4.5 10²² ~m ⁻³ . The doped semiconductor is of
Options
- An -type with electron concentration n_e=5 10²² ~m ⁻³
- Bp -type with electron concentration n_e=2.5 10¹⁰ ~m ⁻³
- Cn-type with electron concentration n_e=2.5 10²³ ~m ⁻³
- Dp-type having electron concentration n_e=5 10^9 ~m ⁻³
Correct answer
D. p-type having electron concentration n_e=5 10^9 ~m ⁻³
Step-by-step solution
aligned & n_i^2=n_e n_h & n_e= (n_i )^2 n_h & n_e= (1.5 10¹⁶ )^2 (4.5 10²² ) & n_e=5 10^9 ~m ⁻³ aligned So, n_ f₁ n_e semiconductor is p -type.