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Line 87: − Since no free charge carriers can rest in a position where there is a potential barrier, the regions on either sides of the junction now become completely depleted of any more free carriers in comparison to the N and P type materials further away from the junction. This zone around the '''PN Junction''' is now called the '''Depletion''' Layer. − + Line 119:
Line 118: − . − −
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In other words, charged carriers that have already crossed the junction set up an electric force (field) that acts as a barrier opposing the further flow of free carriers. As more carriers cross the junction, the barrier enlarges, making it increasingly difficult for other carriers to cross. Eventually, an equilibrium is established where (statistically speaking) no more electrons or holes switch sides.
In other words, charged carriers that have already crossed the junction set up an electric force (field) that acts as a barrier opposing the further flow of free carriers. As more carriers cross the junction, the barrier enlarges, making it increasingly difficult for other carriers to cross. Eventually, an equilibrium is established where (statistically speaking) no more electrons or holes switch sides.
Since no free charge carriers can rest in a position where there is a potential barrier, the regions on either sides of the junction now become completely depleted of any more free carriers in comparison to the N and P type materials further away from the junction. This zone around the '''PN Junction''' is now called the '''Depletion''' Layer.
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If we then connect the n-type side to the p-type side of the cell by means of an external electric circuit, current flows through the circuit (which responds just as if powered by a battery} because this reduces the light induced charge imbalance in the cell.
If we then connect the n-type side to the p-type side of the cell by means of an external electric circuit, current flows through the circuit (which responds just as if powered by a battery} because this reduces the light induced charge imbalance in the cell.
Negative charges flow out of the electrode on the n-type side, through a load (such as a light bulb}, and perform useful work on that load (such as heating the light bulb's filament to incandescence}. The electrons then flow into the p-type side, where they recombine with holes near the electrode.[[File:PV cell in circuit.png|left|thumb|350x350px]]
Negative charges flow out of the electrode on the n-type side, through a load (such as a light bulb}, and perform useful work on that load (such as heating the light bulb's filament to incandescence}. The electrons then flow into the p-type side, where they recombine with holes near the electrode.[[File:PV cell in circuit.png|left|thumb|350x350px]]