# Semiconductor Photodiodes without Internal Gain

This set of Optical Communications Multiple Choice Questions & Answers focuses on “Semiconductor Photodiodes Without Internal Gain”.

1. The width of depletion region is dependent on ___________ of semiconductor.
a) Doping concentrations for applied reverse bias
b) Doping concentrations for applied forward bias
c) Properties of material
d) Amount of current provided

2. Electron-hole pairs are generated in ___________
a) Depletion region
b) Diffusion region
c) Depletion region
d) P-type region

3. The diffusion process is _____________ as compared with drift.
a) Very fast
b) Very slow
c) Negligible
d) Better

4. Determine drift time for carrier across depletion region for photodiode having intrinsic region width of 30μm and electron drift velocity of 105 ms-1.
a) 1×10-10 Seconds
b) 2×10-10 Seconds
c) 3×10-10 Seconds
d) 4×10-10 Seconds

5. Determine intrinsic region width for a photodiode having drift time of 4×10-10 s and electron velocity of 2×10-10ms-1.
a) 3×10-5M
b) 8×10-5M
c) 5×10-5M
d) 7×10-5M

6. Determine velocity of electron if drift time is 2×10-10s and intrinsic region width of 25×10-6μm.
a) 12.5×104
b) 11.5×104
c) 14.5×104
d) 13.5×104

7. Compute junction capacitance for a p-i-n photodiode if it has area of 0.69×10-6m2, permittivity of 10.5×10-13Fcm-1 and width of 30μm.
a) 3.043×10-5
b) 2.415×10-7
c) 4.641×10-4
d) 3.708×10-5

8. Determine the area where permittivity of material is 15.5×10-15Fcm-1 and width of 25×10-6 and junction capacitance is 5pF.
a) 8.0645×10-5
b) 5.456×10-6
c) 3.0405×10-2
d) 8.0645×10-3

9. Compute intrinsic region width of p-i-n photodiode having junction capacitance of 4pF and material permittivity of 16.5×10-13Fcm-1 and area of 0.55×10-6m2.
a) 7.45×10-6
b) 2.26×10-7
c) 4.64×10-7
d) 5.65×10-6

10. Determine permittivity of p-i-n photodiode with junction capacitance of 5pF, area of 0.62×10-6m2 and intrinsic region width of 28 μm.
a) 7.55×10-12
b) 2.25×10-10
c) 5×10-9
d) 8.5×10-12

11. Determine response time of p-i-n photodiode if it has 3 dB bandwidth of 1.98×108Hz.
a) 5.05×10-6sec
b) 5.05×10-7Sec
c) 5.05×10-7sec
d) 5.05×10-8Sec

12. Compute maximum 3 dB bandwidth of p-i-n photodiode if it has a max response time of 5.8 ns.
a) 0.12 GHz
b) 0.14 GHz
c) 0.17 GHz
d) 0.13 GHz

13. Determine maximum response time for a p-i-n photodiode having width of 28×10-6m and carrier velocity of 4×104ms-1.
a) 105.67 MHz
b) 180.43 MHz
c) 227.47 MHz
d) 250.65 MHz

14. Determine carrier velocity of a p-i-n photodiode where 3dB bandwidth is1.9×108Hz and depletion region width of 24μm.
a) 93.43×10-5
b) 29.55×10-3
c) 41.56×10-3
d) 65.3×10-4

15. Compute depletion region width of a p-i-n photodiode with 3dB bandwidth of 1.91×108and carrier velocity of 2×104ms-s.
a) 1.66×10-5
b) 3.2×10-3
c) 2×10-5
d) 2.34×104