P-N junction - Need explanation \"...Recall that the n-side isstudded throughout

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P-N junction - Need explanation "...Recall that the n-side isstudded throughout with positively charged donor ions, fixed firmlyin their lattice sites. Normally, the excess positive charge ofeach of these ions is compensated electrically by one of theconduction band electrons. When an n-side electron diffuses acrossthe junction plane, however, the diffusion uncovers one of thesedonor ions, thus introducing a fixed position charge near thejunction plane on the n-side. When the diffusing electron arriveson the p-side, it quickly combines with an acceptor ion (whichlacks one electron), thus introducing a fixed negative charge nearthe junction plane on the p-side. In this way, diffusion ofelectrons results in the build up of space charge on each side ofthe junction plane. HOLES DIFFUSING THROUGH THE JUNCTION PLANE FROMP TO N-SIDE HAVE EXACTLY THE SAME EFFECT. (TAKE THE TIME NOW TOCONVINCE YOURSELF OF THAT)......"
There's the problem for me, I'm unable to grasp what willhappen when the holes enter the n-side.
Can anyone please fill that in for me?
Can you also explain... "...introducing a fixed position chargenear the junction plane on the n-side...." why near the junctionplane? Why not in the centre or the side away from theplane?

Thanking in advance... P-N junction - Need explanation "...Recall that the n-side isstudded throughout with positively charged donor ions, fixed firmlyin their lattice sites. Normally, the excess positive charge ofeach of these ions is compensated electrically by one of theconduction band electrons. When an n-side electron diffuses acrossthe junction plane, however, the diffusion uncovers one of thesedonor ions, thus introducing a fixed position charge near thejunction plane on the n-side. When the diffusing electron arriveson the p-side, it quickly combines with an acceptor ion (whichlacks one electron), thus introducing a fixed negative charge nearthe junction plane on the p-side. In this way, diffusion ofelectrons results in the build up of space charge on each side ofthe junction plane. HOLES DIFFUSING THROUGH THE JUNCTION PLANE FROMP TO N-SIDE HAVE EXACTLY THE SAME EFFECT. (TAKE THE TIME NOW TOCONVINCE YOURSELF OF THAT)......"
There's the problem for me, I'm unable to grasp what willhappen when the holes enter the n-side.
Can anyone please fill that in for me?
Can you also explain... "...introducing a fixed position chargenear the junction plane on the n-side...." why near the junctionplane? Why not in the centre or the side away from theplane?

Thanking in advance...

Explanation / Answer

Given :   p–n junction is a junction formed by joiningP-type and N-type semiconductors together in very closecontact. The term junction refers to the region where the tworegions of the semiconductor meet. It can be thought of as theborder region between the p-type and n-type blocks . The p–n junction possesses some interestingproperties which have useful applications in modern electronics. Ap-doped semiconductor is relatively conductive. The same is true ofan n-doped semiconductor, but the junction between them is anonconductor. This nonconducting layer, called the depletion zone ,occurs because the electrical charge carriers in doped n-type andp-type silicon (electrons and holes, respectively) attract andeliminate each other in a process called recombination. Electrons near the p–n interface tend to diffuseinto the p region. As electrons diffuse, they leave positivelycharged ions (donors) in the n region. Similarly holes near the p–ninterface begin to diffuse into the n-type region leaving fixedions (acceptors)with negative charge. The regions nearby the p–ninterfaces lose their neutrality and become charged, forming thespace charge region or depletion layer. I hope it helps you

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