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”.

In the problems assume the parameter given in the following table. Use the temperature T= 300 K unless otherwise stated.

1. In germanium semiconductor material at T 400 K the intrinsic concentration is (x 10^14 per cc)
a) 26.8
b) 18.4
c) 8.5
d) 3.6
View Answer

Answer: c
Explanation:

2. The intrinsic carrier concentration in silicon is to be no greater than ni = 1 x 10^12 cc. The maximum temperature allowed for the silicon is ( Eg = 1.12 eV)
a) 300 K
b) 360 K
c) 382 K
d) 364 K
View Answer

Answer: c
Explanation:

3. Two semiconductor material have exactly the same properties except that material A has a bandgap of 1.0
eV and material B has a bandgap energy of 1.2 eV. The ratio of intrinsic concentration of material A to that of
material B is
a) 2016
b) 47.5
c) 58.23
d) 1048
View Answer

Answer: b
Explanation:

4. In silicon at T = 300 K the thermal-equilibrium concentration of electron is n0 = 5 x 10^4 cc. The hole concentration is
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 silicon at T = 300 K if the Fermi energy is 0.22 eV above the valence band energy, the value of p0 is
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 hole p0 in silicon at T = 300 K is 1015 cm3. The value of n0 is
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 germanium semiconductor at T 300 K, the acceptor concentrations is Na 1013 cm3 and donor concentration is Nd 0. The thermal equilibrium concentration p0 is
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 doped n type at 10^18 cm3 have a resistance of 10 ohm. The sample has an area of 10^(-6) cm2 and a length of 10 µm . The doping efficiency of the sample is (µn = 800 cm2/V-s )
a) 43.2%
b) 78.1%
c) 96.3%
d) 54.3%
View Answer

Answer: b
Explanation:

9. Six volts is applied across a 2 cm long semiconductor bar. The average drift velocity is 104 cms. The electron mobility is
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 (ohm-cm) at T = 300 K and 5 (ohm-cm) at T = 330 K. If change in mobility with temperature is neglected, the bandgap energy of the semiconductor is
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.

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