MATTER LogoIntroduction to Electrons in Crystals

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Conduction > Introduction

Description of Flash Animation.

This animation shows the bar of the conductor when a potential is applied to a metal, an intrinsic semiconductor, a p-type semiconductor and an n-type semiconductor. The bands for each of these is also shown.

This resource requires Flash Player 9 or above available to download from http://www.adobe.com/go/getflash

Question
What limits the number of electrons available for conduction in an n-type semiconductor at room temperature?

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Electrical conduction occurs in most circumstances by the transport of electrons or holes or both, although there are exceptions. When a potential is applied (ie, in an electric field) electrons travel towards the positive pole and holes to the negative.

Exceptions

Current can also be carried by ions or any charged particle if these are mobile.

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The nature of the majority carrier depends on the band structure of the conductor. Only electrons or holes which can increase their energy slightly can contribute to conduction. In practice, this means electrons near the Fermi level in a metal or carriers close to the band edges in a semiconductor.

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Question

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