COMEDK · Physics · 30. Semiconductors
A silicon sample is doped simultaneously with donor impurity phosphorus at a concentration of \(N_D = 3 \times 10^{22}\ m^{-3}\) and acceptor impurity boron at a concentration of \(N_D = 2.8 \times 10^{22}\ m^{-3}\). The intrinsic carrier concentration of silicon at room temperature is \(n_i = 1.5 \times 10^{16}\ m^{-3}\). Assuming complete ionization, the hole concentration is:
A. \(1.125 \times 10^{10}\ m^{-3}\)
B. \(1.125 \times 10^{11}\ m^{-3}\)
C. \(2.125 \times 10^{10}\ m^{-3}\)
D. \(2.125 \times 10^{11}\ m^{-3}\)
- A \(1.125 \times 10^{10}\ m^{-3}\)
- B \(1.125 \times 10^{11}\ m^{-3}\)
- C \(2.125 \times 10^{10}\ m^{-3}\)
- D \(2.125 \times 10^{11}\ m^{-3}\)
Answer & Solution
Correct Answer
(B) \(1.125 \times 10^{11}\ m^{-3}\)
Step-by-step Solution
Detailed explanation
Given donor concentration \(N_D = 3 \times 10^{22}\ m^{-3}\) and acceptor concentration \(N_A = 2.8 \times 10^{22}\ m^{-3}\). Since \(N_D > N_A\), the semiconductor is n-type. The effective donor concentration is…
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