1.8. Mass Action Law

Try these first

1. 1.

   What does the Mass Action Law state about intrinsic semiconductors?

   Hint

   Think about how the charge carriers interact in an intrinsic semiconductor.

2. 2.

   Define intrinsic carrier concentration.

   Hint

   It’s a key characteristic of intrinsic semiconductors.

3. 3.

   What is the mathematical expression of the Mass Action Law?

   Hint

   Look for the equation relating n and p to ni.

4. 4.

   True or False: The Mass Action Law only applies to n-type semiconductors.

   • True
   • False

   Hint

   Remember that it relates to intrinsic conditions.

5. 5.

   An intrinsic semiconductor has an electron concentration of 2 × 10^10 cm⁻³ at room temperature. Calculate the hole concentration and explain your reasoning based on the Mass Action Law.

   Hint

   Ensure you know how to rearrange the Mass Action Law equation.

6. 6.

   Given that doping a semiconductor with phosphorus increases the electron concentration to 5 × 10^10 cm⁻³, calculate the new hole concentration if ni remains constant at 1 × 10¹⁰ cm⁻³.

   Hint

   Use the Mass Action Law and remember how doping changes the distribution of carriers.