Conductors, Semi-conductors and Insulators
- Created by: Lucy Rennie
- Created on: 15-04-19 14:41
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- Conductors, Semiconductor and Insulators
- Conductors
- Mostly metals conduct electricity
- In conductors, there is no space between the conduction and valence bands
- This allows electrons to move freely through the conduction band allowing them to conduct the electricity
- Insulators
- Only non-metals are insulators
- Insulators have large gaps between the conduction and valence bands
- This means that the electrons cannot move between the valence and conduction bands, and so cannot conduct electricity
- Semi-conductors
- Semi-conductors have small gaps between the conduction and valence bands
- This means that with a small amount of energy (intrinsic) or as a result of doping (extrinsic)
- P-type semi-conductors have more holes in the valence band than electrons in the conduction band
- These occur when a group 4 element is doped with a group three element which has less electrons
- Then the electrons move between the conduction and valence bands to fill the extra hole and so can conduct electricity
- P-type semi-conductors always retain an overall neutral charge
- These occur when a group 4 element is doped with a group three element which has less electrons
- N-type semi-conductors have more electrons in the conduction band than holes in the valence band
- These occur when a group four element is doped with a group five element with more electrons
- This means that the excess electrons are free to move between the conduction and valence band and so can conduct electricity
- N-type semi-conductors always retain an overall neutral charge
- These occur when a group four element is doped with a group five element with more electrons
- Semi-conductors have small gaps between the conduction and valence bands
- Conductors
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