1 / 8

Field and Potential in a Diode – Worked Example

p-type. n-type. Field and Potential in a Diode – Worked Example. A diode is composed of two pieces on n- and p-type silicon, in contact When this is formed, electrons desert the bit of the n region that abuts the p-type and get lost in the bulk of the p region

hisano
Download Presentation

Field and Potential in a Diode – Worked Example

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. p-type n-type Field and Potential in a Diode – Worked Example • A diode is composed of two pieces on n- and p-type silicon, in contact • When this is formed, electrons desert the bit of the n region that abuts the p-type and get lost in the bulk of the p region • Holes from the p-type do the opposite • This leaves a depletion region

  2. Depletion region? Large numbers of positive donor atoms in a small volume Large numbers of negative acceptor atoms in a small volume Small numbers of extra holes in a large volume Small numbers of extra electrons in a large volume -ve charge +ve charge ≈Charge neutral ≈Charge neutral p-type n-type Depletion region

  3. p-type n-type Gauss’s Law • òòD.ds = charge enclosed • Choose a Gaussian surface that looks like the diode

  4. Gaussian surface x |D| Now position it carefully and move it! p-type n-type Depletion region No charge enclosed, no field, constant potential E=-ÑV,D=εE V x

  5. Gaussian surface x |D| Now position it carefully and move it! p-type n-type Depletion region E=-ÑV,D=εE -ve charge enclosed,-ve field increasing,+ve potential V x

  6. Gaussian surface x |D| Now position it carefully and move it! p-type n-type Depletion region +ve charge enclosed,-ve field decreasing,+ve potential E=-ÑV,D=εE V x

  7. Gaussian surface x |D| Now position it carefully and move it! p-type n-type Depletion region equal –ve and +ve charge enclosed,no field, constant +ve potential E=-ÑV,D=εE V x

  8. x |D| p-type n-type Depletion region E=-ÑV,D=εE Actually this shape with such a simplified model V x

More Related