This ionised donor (positive charge) is immobile as it is
bonded to the surrounding atoms As the electrons continue to diffuse
from n ® p, a layer of positive charge (or positive space-charge region) on
n-side of the junction is developed Similarly, when a hole diffuses from p ® n due to the concentration
gradient, it leaves behind an ionised acceptor (negative charge) which is
immobile As the holes continue to diffuse, a layer of negative charge (or
negative space-charge region) on the p-side of the junction is developed