Determine drift time for carrier across depletion region for photodiode having intrinsic region width of 30μm and electron drift velocity of 10 5 ms -1

Optoelectronics and Optical Communication 

Determine drift time for carrier across depletion region for photodiode having intrinsic region width of 30μm and electron drift velocity of 10 5 ms -1

a) 1×10 -10 Seconds 
b) 2×10 -10 Seconds 
c) 3×10 -10 Seconds 
d) 4×10 -10 Seconds

Answer : - 3×10 -10 Seconds

The drift time is given by 
t drift = w/v d = 30×10 -6 /1×10 -10 = 3×10 -10 seconds.