Question

The electric current produced when the charge carrier concentration moves from region of higher concentration to the region of lower concentration is called

• A. Drift current
• B. Diffusion current
• C. Reverse saturation current
• D. Breakdown current

Hint:

Drift current: \(\vec{J}_{drift} = q(n\mu_n + p\mu_p)\vec{E}\).
Diffusion current: \(\vec{J}_{diff} = qD_n \nabla n - qD_p \nabla p\) (for electrons and holes respectively, signs depend on gradient direction).

Answer 1

The Correct Option is B

Current in semiconductors arises from two main mechanisms:
Drift current: Due to the motion of charge carriers under the influence of an electric field.
Diffusion current: Due to the motion of charge carriers from a region of high concentration to a region of low concentration, driven by the concentration gradient. The question describes current due to movement from higher to lower concentration, which is diffusion current. Reverse saturation current is a small current in a reverse-biased diode. Breakdown current is a large current during diode breakdown. \[ \boxed{\text{Diffusion current}} \]