COMEDK · Physics · 30. Semiconductors
An intrinsic semiconductor has equal concentrations of hole and electron which is equal to \(4 \times 10^8 \mathrm{~m}^{-3}\). During its conversion to extrinsic semiconductor, concentration of hole increases to \(8 \times 10^{10} \mathrm{~m}^{-3}\). The new electron concentration is:
- A \(4 \times 10^{10} \mathrm{~m}^{-3}\)
- B \(4 \times 10^8 m^{-3}\)
- C \(2 \times 10^8 m^{-3}\)
- D \(2 \times 10^6 \mathrm{~m}^{-3}\)
Answer & Solution
Correct Answer
(D) \(2 \times 10^6 \mathrm{~m}^{-3}\)
Step-by-step Solution
Detailed explanation
For an intrinsic semiconductor, the intrinsic carrier concentration \(n_i\) is given by \(n_i = n_e = n_h = 4 \times 10^8 \text{ m}^{-3}\). The law of mass action for semiconductors states that the product of electron concentration \(n_e\) and hole concentration \(n_h\) in an…
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