Question

If a P-type semiconductor is brought into contact with an N-type semiconductor, which of the following will happen?

Select one:

a. An electric field will be created which opposes the drift of carriers
b. None of these
c. Minority carriers will diffuse to the opposite side of the PN junction
d. The regions close to the PN junction will become depleted of mobile charge carriers
e. Ions uncovered by drift will create a charge distribution around the PN junction

Answer 1

When a P-type semiconductor comes into contact with an N-type, a depletion region forms at the junction, creating an electric field that opposes carrier movement, and depletes the area of mobile charge carriers.

Step-by-step explanation:

When a P-type semiconductor is brought into contact with an N-type semiconductor, several things occur. Primarily, there is a diffusion of majority carriers across the PN junction, with free electrons from the N-type material moving to fill the holes in the P-type material. This leads to the formation of a depletion region around the junction where mobile charge carriers are depleted. As a result, uncovered ions in this depletion region create an electric field that opposes further carrier diffusion, and in equilibrium, the diffusion and drift currents cancel out, leading to no net current. So, the regions close to the PN junction become depleted of mobile charge carriers, and an electric field is created which opposes the drift of carriers. Consequently, the correct answer is a couple of the options provided, namely: 'An electric field will be created which opposes the drift of carriers' and 'The regions close to the PN junction will become depleted of mobile charge carriers'.