Identify the correct statement(s) among the following.
(A) Electrical conductivity in an intrinsic semiconductor is due to electrons excited from the conduction band to valence band.
(B) In germanium atom electrical conductivity is due to intrinsic charge carriers.
(C) In doped atoms, the size of the dopant atom should be almost the same as that of the intrinsic crystal.
(D) In n-type semiconductor, the donor atom becomes negatively charged.
Choose correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (B) and (C) only
(A) Incorrect → Conductivity is due to electrons excited from the valence band to conduction band, not the other way around.
(B) Correct → In pure Ge, conduction is due to intrinsic carriers (electrons and holes).
(C) Correct → Dopant atom should be nearly the same size as host atom to fit in the lattice without distortion.
(D) Incorrect → In n-type, donor atom loses electron and becomes positively charged, not negative.
Final Answer: (B), (C)