We can think of the electrons behaving as water droplets Sin

We can think of the electrons behaving as water droplets. Since holes are missing electrons, they can be thought of as the bubbles i.e. missing water. Consider an electron in the depletion region of the p-n junction. For the electron to lower its energy, which way would it move (left or right)? Considering the hole is a missing electron, for the system to lower its energy which way will the hole move (left or right)?

Solution

3. In depletion region of a p-n junction a potenial barrier, which is monotonoulsy increasing from n side to p side, is created for Electrones in n region. So any electron in depletion region shall not be able to cross this barrier unless a greater potential applied externally . So any electron in depletion region shall move away from juction (right) to lower its energy level.

4.In depletion region of a p-n junction a potenial barrier, which is monotonoulsy increasing from p side to n side, is created for Holes in p region. So any hole in depletion region shall not be able to cross this barrier unless a greater potential applied externally . So any hole in depletion region shall move away from juction (left) to lower its energy level.