Question

Which of the following represents the best definition for the diffusion length for holes?

(a) Average distance which an electron is injected travels before recombining with an electron

(b) Average distance which a hole is injected travels before recombining with an electron

(c) Average distance which a hole is injected travels before recombining with a hole

(d) Average distance which an electron is injected before recombining with a hole

I have been asked this question during a job interview.

My doubt stems from The Continuity Equation in chapter Conduction in Semiconductors of Electronic Devices & Circuits

Answer 1

Correct choice is (b) Average distance which a hole is injected travels before recombining with an electron

The best I can explain: Diffusion length for holes is represented as the average distance which a hole is injected travels before recombining with an electron. It is the distance into the semiconductor at which the injected concentration falls to 1/ϵ of its value at x=0.