Question

Why does the thickness of depletion layer of pn-junction increases in reverse biasing ?Draw the circuit diagram of reverse biasing.

Answer 1

If a diode is reverse-biased, the voltage at the cathode is comparatively higher than the anode. Therefore, no current will flow until the diode breaks down.
Because the p-type material is now connected to the negative terminal of the power supply, the 'holes' in the p-type material are pulled away from the junction, leaving behind charged ions causing the width of the depletion region to increase.