| MadSci Network: Physics |
Hi Hari,
A positron is the positively charged counterpart of an electron,
a real particle that can be generated and detected in particle
accelerators. It has the same mass and properties as an electron.
When it finds an electron, which are abundant in any matter, both
annihilate and emit light. Positrons can thus only survive in
vacuum.
A hole is a "missing" electron in a crystal lattice where every
electron has its well defined place. Holes have a positive charge
(a missing negative one is by definition positive), and mass and
other properties are different from electrons. Holes in p-doped
semiconductor contribute to electric conductivity by allowing
electrons to "hop" from one lattice position to the next. In n-
doped material, excess electrons "squeeze" through the lattice
positions, which are all filled. A hole and an excess electron
together annihilate and emit light (e.g. in an LED). There are
no holes outside of crystal lattices.
Greetings from Indonesia,
Frank
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