Doping Part one

Dopants increase the conductivity of

semiconductors by _____.

• increasing the forbidden gap

• turning them into insulators

• adding net charge to the semiconductor

• making extra electrons or holes available

• turning them into intrinsic semiconductors

A hole refers to ______.

• a proton

• a positively charged electron

• a microscopic defect in a solid

• an electron which has somehow lost its

  charge

• the absence of an electron in an otherwise

  filled band

Which of the following is/are true for an intrinsic

semiconductor?

I. Pure semiconductor

II. Have low conductivity

III. Conducts due to thermally freed electrons

• I only

• II only

• III only

• I and III

• I, II and III

Which of the following elements has the correct

number of valance electrons to be used as a dopant

for an 𝑛 −type semiconductor?

• Beryllium (𝑍 = 4)

• Boron (𝑍 = 5)

• Nitrogen (𝑍 = 7)

• Aluminum (𝑍 = 13)

• None of the above

How do dopants increase the conductivity of

semiconductors?

• They add net charge to the semiconductor

• They increase the forbidden gap

• They make extra electrons or holes

  available

• They turn them into intrinsic

  semiconductors

• They always decrease the number of

  charge carriers

Dopants are used to _____ semiconductors.

• increase the conductivity of extrinsic

• increase the heat generated by

• increase the conductivity of intrinsic

• decrease the heat generated by

• increase the heat generated by

Conduction is increased in an 𝑛 −type

semiconductor by _____.

• increased applied electrical field

• decreased applied electrical field

• the availability of extra holes

• the availability of donor electrons

• the availability of extra holes and donor

  electrons

Dopant atoms that increase conductivity are

added to a semiconductor to produce ____.

• a conductor

• an insulator

• a pure semiconductor

• an intrinsic semiconductor

• an extrinsic semiconductor

When dopants are added to a semiconductor, the

net charge of the material ____.

• remains zero

• becomes zero

• becomes positive

• becomes negative

• becomes positive or negative depending

  on the dopant added

Dopant atoms that increase conductivity are

added to a semiconductor to produce ____.

• a conductor

• an insulator

• a pure semiconductor

• an intrinsic semiconductor

• an extrinsic semiconductor