Topic: Electronic Devices and Circuits
Which of the following conditions will maximize the diffusion current in a semiconductor?
- A. Uniform doping profile
- B. High electric field
- C. Steep concentration gradient
- D. Zero temperature gradient
Answer: C. Steep concentration gradient
Explanation: Diffusion current in a semiconductor occurs due to the random thermal motion of charge carriers from a region of high concentration to a region of low concentration. It is governed by Fick's first law, making it directly proportional to the concentration gradient (e.g., $J_p = -q D_p \frac{dp}{dx}$). Therefore, a steep (large) concentration gradient will maximize the diffusion current.