Why Semiconductor does not obey Ohm's Law? Explained


The semiconductor does not obey Ohm's law because it has opposite properties than a conductor and it has non-linear property. Let's explain in detail.

We know that according to the Ohm's law the flow of current through a conductor is directly proportional to the potential difference between the two ends of that conductor when temperature and other physical quantity are constant.

So according to Ohm's law,

V I

Where V= voltage or potential difference
            I = Current

According to Ohm's law, the VI characteristics are given below,

ohms law characteristics


So as you see in the above graphical diagram according to the Ohm's law the changes in current with voltage should be linear.




Now let's talk about the semiconductor. A semiconductor has non-linear property. If we see the VI characteristics of the normal PN Junction diode which is a semiconductor device, then we will see the VI characteristics of Diode is nonlinear.

diode characteristics


So for the non-linear characteristics, Semiconductor does not obey Ohm's Law.


Another Reason,

When the temperature of semiconductor is increased then the covalent bonds break quickly, as a result, the free charge carriers are increasing. So more electrons coming from the valence band to conduction band. So it is clear that when the temperature increases the conduction of semiconductor increases and resistance decreases.

temperature vs resistivity for conductor and semiconductor


But in the case of a conductor, the resistivity increases with increasing temperature. So the temperature vs resistivity property of conductor and semiconductor is completely opposite. This may be a reason of Semiconductor does not obey Ohm's Law.




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Why Semiconductor does not obey Ohm's Law? Explained Why Semiconductor does not obey Ohm's Law? Explained Reviewed by ETechnoG on 17:54 Rating: 5
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