- #1
iampaul
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I am currently taking up a course in electronic devices and circuits. Our first topic was about semiconductors and I'm having trouble understanding the doping process. We didn't have any prerequisite solid state course or any other course related to it that's why my professor explains the concepts qualitatively. We didn't tackle concepts i see in the internet like mobility, fermi energy....and i have no idea what those are. I want to try and study those concepts by myself, but i suppose they require higher levels of physics, than what i currently know. It would consume too much time and it might affect my performance in my other subjects.
My problem is about minority and majority carriers:
If silicon is doped with a pentavalent atom, the four valence electrons of silicon will form covalent bonds with four valance electrons of the pentavalent atom and there is an unpaired electron from the pentavalent atom. It acts as a free carrier electron. What i don't understand is why should there be minority carriers. With all those covalent bonds there are initially only unpaired free electrons and i think there should be no holes . A hole appears when the free electron moves but then the number of free electrons must be the same as the number of holes. My question is how can we say that the electrons are the majority carriers and the holes are the minority??
I have the same problem with silicon doped with a trivalent atom
Please help, Thanks in advance =)
My problem is about minority and majority carriers:
If silicon is doped with a pentavalent atom, the four valence electrons of silicon will form covalent bonds with four valance electrons of the pentavalent atom and there is an unpaired electron from the pentavalent atom. It acts as a free carrier electron. What i don't understand is why should there be minority carriers. With all those covalent bonds there are initially only unpaired free electrons and i think there should be no holes . A hole appears when the free electron moves but then the number of free electrons must be the same as the number of holes. My question is how can we say that the electrons are the majority carriers and the holes are the minority??
I have the same problem with silicon doped with a trivalent atom
Please help, Thanks in advance =)