johanfprins
Graduate Poster
- Joined
- Dec 1, 2010
- Messages
- 1,015
Now I can again get back to Ben's little games based on being deliberately leading the discussion away from the main topic.
What has this to do with a metal to n-type semiconductor contact?In case it helps, which I doubt, let me challenge you with another thought experiment. Consider a gold block and a sodium block; neutral and NOT in contact.
How do you lower this electron into the sodium? Nowhere have I claimed that I first extract an electron from one material into the vacuum and then "lower" this electron into another material.It is clear that their Fermi levels are different---if I want to take an electron out of the gold into the vacuum, I have to expend 5.1 eV; if I lower this electron into the sodium, I only gain 2.3 eV.
When you make contact between the two materials there MUST be a field owing to the momentary offset between the Fermi-levels. This has NOTHING to do with extracting an electron into the vacuum from one material and then "lowering" it into another material.According to your mental picture, this difference must represent an electric field.
Why will there be a vacuum between the two materials when they are making contact?Where is the field? In the vacuum between the blocks?
You are obviously again being deluded, or delibertaely trying to confuse the discussion with irrelevant nonsensical examples. I have so far not talked about a vacuum between two materials, but only about the momentary electric field across the interface between them just after having made contact.No it isn't, the field here is zero. (It's a vacuum, I can use Gauss's Law.) At the surface of the metal? No it isn't; if I drop a proton or a positron onto either block, it doesn't feel the Fermi level difference at all.
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