SEMICONDUCTORS & SUPERCONDUCTORS

A semiconductor is a substance whose electrical conductivity lies between:

• Metals and Non-metals

• Insulators and Conductors

• Solids and Liquids

• None of these

A semiconductor is a substance whose forbidden energy is less than

Which of the following is an intrinsic semiconductor?

• Silicon

• Copper

• Silver

• Aluminium

The conductivity of a semiconductor increases with:

• Increase in temperature

• Decrease in temperature

• Pressure

• None of these

An extrinsic semiconductor is formed by:

• Pure material only

• Metals

• Doping an impurity into intrinsic semiconductor

• Alloys

Stoichiometric semiconductors are those in which:

• Structure is amorphous

• Impurities are intentionally added

• Excess atoms are always present

• Exact ratio of constituent elements is maintained

Non-stoichiometric semiconductors are characterized by:

• Complete insulators

• High electrical conductivity like metals

• Deficiency or excess of constituent atoms

• Perfect crystal structure

Zinc oxide (ZnO) with oxygen deficiency acts as:

• p-type semiconductor

• n-type semiconductor

• Insulator

• Metal

In forward bias of a PN junction diode, the barrier potential:

• Decreases

• Increases

• Remains constant

• Becomes zero

The depletion region in a PN junction is formed due to:

• Heating effect

• Applied external voltage
  

• Diffusion of charge carriers across the junction

• Free movement of electrons only