NTA Abhyas JEE Main2020PhysicsSemiconductorsPractice
The density of electron-hole pair in a pure germanium is 3 × 10 16 m - 3 at room temperature. On doping with aluminium, the hole density increases to 4.5 × 10 22 m - 3 . Now, the electron density i n m - 3 in doped germanium will be
Options
- A1 × 10 10
- B2 × 10 10
- C0.5 × 10 10
- D4 × 10 10
Correct answer
B. 2 × 10 10
Step-by-step solution
n i = 3 × 10 16 m - 3 n h = 4.5 × 10 22 m - 3 n e = ? n e n h = n i 2 ⇒ n e = n i 2 n h = 3 × 10 16 2 4.5 × 10 22 = 9 × 10 32 4.5 × 10 22 = 2 × 10 10