Why is the space charge area with high doping concentration rather narrow?

One explanation: The high-doped P-zone, the narrower regions contribute enough holes to offset the electrons contributed by the N-zone.

Another explanation is that the so-called hole in the P-type semiconductor is electrically neutral, and the free electrons in the N-type semiconductors run out of the donor impurity. When P-and n-forms are tightly bound together to form a PN junction, each free electron enters the P-type region and the hole is combined, with a real anion (the hole that combines the free electrons) and a true positive ion (the donor impurity that lost the electron).
So, these two positive and negative ions all exist in the space charge area, so these things are all paired up. Therefore, the space charge zone is electrically neutral.
Due to the positive and negative ions, and the positive ions appear in the space charge region of the N-type region, the negative ions appear in the space charge region of the P-type region, so the respective total amount of the two charges equal, resulting in the space charge area generally appear electrically neutral. If the doping concentration of P-type and N-type semiconductor is different, then the amount of ions in the unit volume can be different, so the volume required to produce the same amount of positive and negative ions is different, here is reflected as the space charge region extends to the respective semiconductor region of different lengths, The space charge region length of P-type and N-type is different. In the same vein, it can also explain why the PN Junction narrows in the case of high doping.

Why is the space charge area with high doping concentration rather narrow?