EE211B Quizizz #5

In an intrinsic semiconductor, electron and hole concentrations are equal at which temperature?

• 0 K

• Low Temperature

• High Temperature

• All Temperature

In an intrinsic semiconductor, the Fermi level

• may be anywhere in the forbidden energy gap

• lies near or at the center of forbidden energy gap

• is near the conduction band

• is near the valence band

For silicon, the energy gap at 300 K is

• 1.1 W

• 1.1 J

• 1.1 eV

• None of these

Consider a semiconductor moderately doped with Arsenic atoms at room temperature. Where do you expect the Fermi level to be?

• in the lower half of the bandgap

• near the middle of the bandgap

• in the upper half of the bandgap

• inside the conduction band

According to Band Theory of Solids, what can be said about the relationship between band-gap width and the tendency of material to conduct electricity?

• The greater the band-gap width the less conductive is the material

• The lesser the band-gap width the more insulating is the material

• The greater the band-gap width the more conductive is the material

In doped (extrinsic) semiconductors, the predominant current carriers are called majority charge carriers, and secondary carriers are called minority. Which statement is true for N-and P-type semiconductors:

• In N-type semiconductors, electrons are majority carriers and holes are minority carriers

• In P-type semiconductors, majority carriers are electrons, and minority charge carriers are holes

• In N-type semiconductors, both types of carriers are equally present

When Silicon (Si) is doped with one of the following elements, it acquires P-type conductivity (holes are the majority carriers). Choose the one:

• Phosphorus (P), valence V

• Tin (Sn), valence IV

• Boron (B), valence III

Silicon is doped with boron to a concentration of 4 × 10¹⁷ 𝑎𝑡𝑜𝑚𝑠/𝑐𝑚³. Assume the intrinsic carrier concentration of silicon to be 1.5 × 10¹⁰/𝑐𝑚³ at 300 K. Compared to un - doped silicon, the Fermi level of doped silicon.

• Goes down by 0.13 eV

• Goes up by 0.13 eV

• Goes down by 0.44 eV

• Goes up by 0.44 eV