|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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