Drift current Is of PN junction under open-circuit conditions

In summary, The discussion is about drift current Is of a PN junction under open-circuit conditions. The person is confused about why Is is independent of the depletion layer voltage Vo and believes that Vo plays a role in creating an electric field that helps establish Is. However, the other person explains that the generation process of minority carriers does not depend on voltage and that it is assumed all generated carriers reach the junction.
  • #1
anhnha
181
1
Hi,
I need help to understand this section from my book.
attachment.php?attachmentid=59537&stc=1&d=1371176509.jpg

attachment.php?attachmentid=59538&stc=1&d=1371176509.jpg


Here we are considering drift current Is of PN junction under open-circuit conditions.
I don't understand why the drift current Is is indepentent of the value of the depletion layer voltage Vo.
I think the voltage create an electric field that helps minority charges in N, P materials establishing drift current Is. Therefore, it is of course dependent on Vo.
Can you tell me where I am wrong here?
 

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  • #2
I think it is assumed that all generated minority carriers reach the junction. The generation process does not depend on the voltage.
 

Related to Drift current Is of PN junction under open-circuit conditions

1. What is drift current in a PN junction under open-circuit conditions?

Drift current is the movement of charge carriers (electrons and holes) within a PN junction when there is a potential difference across the junction. Under open-circuit conditions, the potential difference is zero, so the drift current is minimal.

2. How does drift current affect the behavior of a PN junction under open-circuit conditions?

In an ideal PN junction, the drift current is balanced by the diffusion current, resulting in no net current flow. However, in real-world PN junctions, there may be a small amount of drift current that can cause minor leakage currents.

3. What factors influence the magnitude of drift current in a PN junction under open-circuit conditions?

The magnitude of drift current is dependent on the doping concentration, the voltage applied to the junction, and the temperature. Higher doping concentrations and higher voltages can result in larger drift currents, while higher temperatures can decrease the drift current.

4. Why is drift current important in the operation of PN junction devices?

Drift current is an important factor in the performance of PN junction devices because it affects the overall current flow and can lead to leakage currents and other undesirable effects. Understanding and controlling drift current is crucial for optimizing the performance of these devices.

5. How can drift current be minimized in a PN junction under open-circuit conditions?

To minimize drift current, the doping concentration of the PN junction can be adjusted to reduce the electric field within the junction. Additionally, using a lower operating voltage or lower temperatures can also help reduce the drift current. However, these adjustments must be carefully considered to avoid negatively impacting other aspects of device performance.

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