|MadSci Network: Physics|
Hello, Durga. Your question is an excellent one – it made me go right back to the basics of how we describe electrons and holes in semiconductors. The short answer is that conduction electrons live in the conduction band and holes live in the valence band, and the behavior of electrons in each of these bands is different. One of the things that is different is the mobility – so it makes sense that conduction electron mobilities are different than the hole mobilities, where the electrons that have to get out of the way of the hole are in a different band. A longer answer would wind up being too long – there are just too many issues involved in describing why different electronic bands behave differently. Even the concept of a “energy band” could take a long time to explain, so I’ll have to assume that if you’ve been introduced to holes and mobility, you can access your own sources to flesh out the details. Good luck.
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