Why isn't the depletion layer width equal in the p and n

[shaylen124]

Hello, I've been researching photovoltaics and I've seen some articles which state that the width of the depletion layer is not equal on both sides on the pn junction. i don't understand why this occurs I've tried to research why and how this happens but have been unable to find an answer.

 

[phyzguy]

Because the doping level is different on the two sides of the P-N junction. The two sides will have equal charge, so the side with a lower doping will have a wider depletion width.