Electronic Devices and Circuits Questions and Answers – Semiconductor Physics

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Semiconductor Physics”.

1. In germanium semiconductor material at T = 400 K the intrinsic concentration is (x 10¹⁴ per cc)
a) 26.8
b) 18.4
c) 8.5
d) 3.6
View Answer

Answer: c
Explanation:

2. For silicon to maintain an intrinsic carrier concentration of n_i ≤ 1 × 10¹² cm^-3, what is the maximum allowable temperature, given that the bandgap energy E_g of silicon is 1.12 eV?
a) 300 K
b) 360 K
c) 382 K
d) 364 K
View Answer

Answer: c
Explanation:

3. Two semiconductor materials, A and B, have identical properties except for their bandgap energies. Material A has a bandgap of 1.0 eV, while material B has a bandgap of 1.2 eV. What is the approximate ratio of the intrinsic carrier concentration of material A to that of material B?
a) 2016
b) 47.5
c) 58.23
d) 1048
View Answer

Answer: b
Explanation:

4. In a silicon semiconductor at T = 300 K, the thermal-equilibrium concentration of electrons is n₀ = 5 × 10⁴ cm^-3. Given that the intrinsic carrier concentration n_i for silicon at T = 300 K is 1.5 × 10¹⁰ cm^-3, what is the hole concentration?
a) 4.5 x 10¹⁵ cc
b) 4.5 x 10¹⁵ m³
c) 0.3 x 10^-6 cc
d) 0.3 x 10^-6 m³
View Answer

5. In a silicon semiconductor at T = 300 K, if the Fermi energy is 0.22 eV above the valence band energy, what is the approximate value of the hole concentration p₀, given that n_i = 1.5 × 10¹⁰ cm^-3?
a) 2 x 10¹⁵ cm³
b) 10¹⁵ cm³
c) 3 x 10¹⁵ cm³
d) 4 x 10¹⁵ cm³
View Answer

Answer: a
Explanation:

6. The thermal-equilibrium concentration of holes p₀ in silicon at T = 300 K is 10¹⁵ cm^-3. If the intrinsic carrier concentration n_i for silicon at this temperature is 1.5 × 10¹⁰ cm^-3, what is the value of the electron concentration n₀?
a) 3.8 x 10⁸ cm³
b) 4.4 x 10⁴ cm³
c) 2.6 x 10⁴ cm³
d) 4.3 x 10⁸ cm³
View Answer

Answer: b
Explanation:

7. In a germanium semiconductor at T = 300 K, with an acceptor concentration N_a = 10¹³ cm^-3 and donor concentration N_d = 0, what is the thermal-equilibrium hole concentration p₀ if the intrinsic carrier concentration n_i for germanium at this temperature is 2.4 × 10¹³ cm^-3?
a) 2.97 x 10⁹ cm³
b) 2.68 x 10¹² cm³
c) 2.95 x 10¹³ cm³
d) 2.4 cm³
View Answer

Answer: c
Explanation:

8. A silicon sample is doped n-type at 10¹⁸ cm^-3 and has a resistance of 10 Ω. The sample has an area of 10^-6 cm² and a length of 10 µm. Given that the electron mobility µ_n is 800 cm²/V·s, what is the doping efficiency of the sample?
a) 43.2%
b) 78.1%
c) 96.3%
d) 54.3%
View Answer

Answer: b
Explanation:

9. Six volts is applied across a semiconductor bar with a length of 2 cm. If the average drift velocity of electrons is 10⁴ cm/s, what is the electron mobility in the bar?
a) 4396 cm²/V^-s 2
b) 3 x 10⁴ cm²/V^-s
c) 6 x 10⁴ cm²V^-s
d) 3333 cm²/V^-s
View Answer

Answer: d
Explanation:

10. A particular intrinsic semiconductor has a resistivity of 50 Ω·cm at T = 300 K and 5 Ω·cm at T = 330 K. Assuming that mobility does not change with temperature, what is the bandgap energy of this semiconductor?
a) 1.9 eV
b) 1.3 eV
c) 2.6 eV
d) 0.64 eV
View Answer

Answer: b
Explanation:

Sanfoundry Global Education & Learning Series – Electronic Devices and Circuits.

To practice all areas of Electronic Devices and Circuits, here is complete set of 1000+ Multiple Choice Questions and Answers.