Timeline for How can electrons travel from the valence band into the conduction band?
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 2, 2019 at 14:24 | comment | added | The Pointer | Yes, I presumed so. I think I misunderstood what the author was saying. Thanks for the clarification. | |
| Apr 2, 2019 at 14:22 | comment | added | user_na | Sorry my answer should read " If there would be allowed states directly above the VALENCE band" - conduction mand makes no sense... | |
| Apr 2, 2019 at 14:22 | vote | accept | The Pointer | ||
| Apr 2, 2019 at 14:15 | comment | added | user_na | @ThePointer: If there would be allowed states directly above the conduction band, then the electrons would scatter there due to e.g. interactions with phonons (i.e. lattice vibrations) forming a Fermi distribution. But if the gap is big enough, phonon scattering does not provide the energy to excite these electrons to the conduction band. So some materilas are a semiconductor at low temperatures and become a conductor when temperature rises. | |
| Apr 2, 2019 at 14:14 | comment | added | The Pointer | Hmm, I see. So would you say that the author's statement that, if an electron is at the top of an energy band, then there are no allowed states immediately above it, since the forbidden band lies immediately above the top of an allowed band, is a bit misleading? The language seems to imply the electron cannot travel to any higher energy bands and will always be stuck in its current band? | |
| Apr 2, 2019 at 14:11 | history | answered | user_na | CC BY-SA 4.0 |