semiconductor devices

The forbidden energy gap for Silicon is of the order of

• 0.7 eV

• 0.3 eV

• 1.1 eV

• 10 eV

Which of the following acts as a donor impurity in doping process ?

• Arsenic

• Indium

• Gallium

• Boron

The reverse saturation current in a PN Junction diode is only due to _________________.

• minority carriers

• majority carries

• negative ions

• positive ions

conductivity of semiconductor increases with increase in temperature, because

• number density of free charge carriers increases

• relaxation time increases

• both number density of free charge carriers and relaxation time increases

• number density of free charge carriers increases relaxation time decreases but effect of decrease in relaxation time is much less than increase in number density

Which of the following statements is incorrect for the depletion region of a diode?

• There the mobile charges exist.

• Equal number of holes and electrons exist, making the region neutral.

• Recombination of holes and electrons has taken place.

• None of these

Potential barrier developed in a junction diode opposes the flow of

• minority carrier in both regions only

• majority carriers only

• majority carriers only

• holes in p region

The breakdown in a reverse biased p-n junction diode is more likely to occur due to

• large velocity of the minority charge carriers if the doping concentration is small

• large velocity of the minority charge carriers if the doping concentration is large

• strong electric field in a depletion region if the doping concentration is small

• none of these

At absolute zero, Si acts as a

• Semiconductor

• conductor

• Insulator

• Non of these

If a small amount of antimony is added to germanium crystal

• its resistance is increased

• it becomes a p-type semiconductor

• there will be more free electrons than holes in the semiconductor,

• none of these.

n an unbiased p-n junction, holes diffuse from the p-region to n-region because

• free electrons in the n-region attract them

• they move across the junction by the potential difference

• hole concentration in p-region is more as compared to u-region.

• all of these