- #1

- 4

- 0

## Main Question or Discussion Point

Can anyone tell me what is the "Brus Approximation" in case of the bang gap of semiconductors?

- Thread starter String_man
- Start date

- #1

- 4

- 0

Can anyone tell me what is the "Brus Approximation" in case of the bang gap of semiconductors?

- #2

malawi_glenn

Science Advisor

Homework Helper

- 4,786

- 22

what is "bang gap" ?

- #3

- 4

- 0

sorry !!! its just a typing mistake. You can understand what i wanna say.

- #4

malawi_glenn

Science Advisor

Homework Helper

- 4,786

- 22

I have never heard of Brus Approximation, is that also a typo? Can you elaborate a bit?

- #5

Cthugha

Science Advisor

- 1,917

- 266

Brus developed a model to predict the band gap energy of nanocrystallites, quantum dots and other small spherical structures with radius R. Roughly speaking, the approach is to start with the bulk value of the energy gap, add a "particle-in-a-box" like term for electrons and holes using an effective mass approximation for the masses of both and subtracting a term, which corresponds to the Coulomb-attraction between electrons and holes. The particle-in-a-box-term scales with 1/R² and the attraction term scales with 1/R, so in small structures the 1/R²-term dominates.

However this approach uses effective masses, which do not depend on the size of the structure. Therefore the results are ok for structures of intermediate size, but are rather wrong for very small structures.

- Last Post

- Replies
- 3

- Views
- 2K

- Last Post

- Replies
- 1

- Views
- 2K

- Replies
- 7

- Views
- 3K

- Last Post

- Replies
- 3

- Views
- 3K

- Last Post

- Replies
- 25

- Views
- 5K

- Last Post

- Replies
- 3

- Views
- 1K

- Replies
- 7

- Views
- 3K

- Replies
- 4

- Views
- 3K