CUET LEVEL II PHYSICS HOMEWORK - SEMICONDUCTOR ELECTRONICS

In germanium semiconductor material at T 400 K the intrinsic concentration is (x 10^14 per cc

• 26.8
  

• 18.4
  

• 8.5
  

• 3.6

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)

• 300 K

• 360 K
  

• 382 K
  

• 364 K

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

• 2016
  

• 47.5
  

• 58.23
  

• 1048

In silicon at T = 300 K the thermal-equilibrium concentration of electron is n0 = 5 x 10^4 cc. The hole concentration is

• 4.5 x 10¹⁵ cc
  

• 4.5 x 10¹⁵ m³
  

• 0.3 x 10^-6 cc
  

• 0.3 x 10^-6 m³

The thermal-equilibrium concentration of hole p0 in silicon at T = 300 K is 1015 cm3. The value of n0 is

• 3.8 x 10⁸ cm³
  

• 4.4 x 10⁴ cm³
  

• 2.6 x 10⁴ cm³
  

• 4.3 x 10⁸ cm³

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 )

• 43.2%
  

• 78.1%
  

• 96.3%
  

• 54.3%

Six volts is applied across a 2 cm long semiconductor bar. The average drift velocity is 104 cms. The electron mobility is

• 4396 cm²/V^-s 2
  

• 3 x 10⁴ cm²/V^-s
  

• 6 x 10⁴ cm²V^-s
  

• 3333 cm²/V^-s

How many junction/s do a diode consist?

• 0
  

• 1
  

• 2
  

• 3

If the positive terminal of the battery is connected to the anode of the diode, then it is known as

• Forward biased
  

• Reverse biased
  

• Equilibrium
  

• Schottky barrier

During reverse bias, a small current develops known as

• Forward current
  

• Reverse current
  

• Reverse saturation current
  

• Active current