Materials  that conduct electricity/current on an atomic level, are materials that  have free electrons that are able to move from atom to atom due to  small distances between each atoms outer electron band.  In turn,  electricity/current is able to flow throughout the material without much  effort. Common conductors would be copper, aluminum, gold, and silver  with copper being the most commonly used conductor due to low cost for  how conductive it is.  Gold and silver conductors are usually used in  situations where high-speed electrical signals need transported, super  high conductivity applications, and resistance to corrosion.  Common  applications for gold and silver would be for motherboards.

For insulators, they resist the flow of electricity/current due to  its’ tight electron bonds to the atom and larger distance between atoms  that make it extremely difficult for the electrons to flow from atom to  atom.  Common insulators are rubber, plastic, dry wood, and glass.   Insulators play a key part in electricity by not only keeping us safe  from electricity, but also isolating electrical circuits therefore the  unique circuits in a system don’t all become one.

Semiconductors fall right in between conductors and insulators.  They  do not have large or small distances between the outer electron bands  usually only allowing electron conductivity with some form of  excitation.  This excitation is usually dependent on whether the  semiconductor is doped or not doped.  If the semiconductor is not doped,  then the excitation usually occurs with temperature increase which  increases conductivity.  Doped semiconductors will be altered to carry a  more positive or negative charge which would create “holes” that would  attract electron.  A common doped semiconductor is a P-N diode which  only allows electricity to flow in one direction.  Most semiconductors  are made from silicon.

One of the coolest semiconductor devices in my opinion would have to  be central processing units (CPUs).  It is insane the amount of  “circuits” and logic that are all with in the CPU. This took computers  from taking up complete buildings with relay logic and now we walk  around with multiple computers every day, like your smart watch, smart  phone, and plenty of other devices.  Especially, whenever you see the  videos where people look at the CPU underneath microscopes and it looks  like mini cities that are more complicated to navigate than New York  City.

References

Conductors and insulators.  Nondestructive Evaluation Physics : Electricity. (n.d.). Retrieved  January 25, 2023, from  https://www.nde-ed.org/Physics/Electricity/conductorsinsulators.xhtml