Question

Question: A sample of silicon doped with antimony is an n-type semiconductor. Suppose a small amount of gallium is added to such a semiconductor. Describe how the conduction properties of the solid will vary with the amount of gallium added.

Short answer

Answer:

The conductivity decreases by decreasing the availability of the electrons. The n-type semiconductor will changes to p-type semiconductor by the adding of Gallium to n-type semiconductor. The conductivity will increases when it changes to p-type semiconductor because more amount of holes.

Step-by-step solution

Step 1:

Silicon have 4 valence electrons and Antimony have 5 valence electrons. If silicon is doped with Antimony, n-type semiconductor will form. With the Silicon atom only 4 bonds are formed.Below the conduction band level the extra electrons present in antimony will occupy.

Step 2:

Gallium have 3valence electrons, In n-type semiconductor if little amount of Gallium is added, in the valence bond there are small positive holes are created and these holes are filled by the extra electrons present in Antimony. In this whole process the conductivity decreases by decreasing the availability of the electrons. The n-type semiconductor will changes to p-type semiconductor by the adding of Gallium to n-type semiconductor. The conductivity will increases when it changes to p-type semiconductor because more amount of holes.