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12. Solids and Modern Material

Chapter 12, Problem 63

A substance has a band gap of 6.9 eV at 273 K. Is this substance best classified as an insulator, a semiconductor, or a metal?

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Hey everyone in this example, we're told that the band gap of a solid is 5.9 electro volts. At 2 73.15 kelvin. We need to classify the following as a metal insulator or a semiconductor. So what we want to think of is a few examples of various elements of our choice. So for our first element, let's go ahead and consider carbon. Where we would specifically think of carbon in the form of a diamond. And we would see that we have a band gap of 5.5 electron volts for carbon and we would label this as an insulator. So we would label carbon in this case as an insulator. Now thinking of another random element, let's think of silicon. Maybe we would see that It has a band gap value of 1.11 Electro volts, when we look that up online or in our textbooks which would correspond based on this value of silicon being a semi conductor. Thinking of another random element, we can think of germanium And we would see that it has a band gap value of 0.67 electra vaults online or in our textbooks. And based on this value, we would label this as a semi conductor. So thinking of one more random element, let's think of tin, we would see that it has a band gap value of 0.8 electro volts. And based on this value, we would label this as just a medal. So based on the info from the prompt, we have a band gap of a solid being 5.9 electro volts. And based on this value, we can compare this to the value that we determined for carbon from our textbooks of 5.5 electron volts, which we stated would make carbon an insulator. And so having a band gap of 5.9 electro volts means that we can label this random solid as also an insulator. So insulator would be our final answer to complete this example. I hope that everything I've read was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.