week 9-10 semiconductor of the week

Wow, I am fascinated to learn about silicon. And really impressed with how the course material is all coming together, building on the previous weeks! Learning about electron orbitals is really coming in handy to understand how a semi-conductor works. So, Silicon has 4 electrons in it's outer orbital, allowing them to form nice crystals -- 4 electrons form perfect covalent bonds with 4 neighboring atoms, creating a lattice. so there are no free electrons to conduct electrical current, making a silicon crystal an insulator rather than a conductor. Metals tend to be good conductors of electricity because they have free electrons moving easily between atoms and electricity involves the flow of electrons. Silicon crystals look metallic but they aren't. BUT then we can "dope" the silicon -- mix in a small amount of an impurity. In N-type doping they mix in an element with 5 outer electrons so that one has nothing to bond with and moves around -- thus conducting electricity, and in P-type doping they mix in an element with 3 outer electrons so there are holes in the silicon lattice, and the holes conduct electricity. And then the real fun begins when you put some N-type lattice together with some P-type lattice. So, silicon can be an insulator and a conductor -- thus the name semi-conductor. I'm getting an appreciation for science in that things actually make sense. Like N-type doping is called that because of the Negative charge and P-type for the Positive charge, and semi-conductors are just what the name implies, they sort of conduct and sort of don't. How refreshing in an often confusing world.

This was also pretty cool to me because I just finished reading a science fiction book where there were these groups of psychic people who would join minds in a circle to do stronger psychic work, and they used these lattices to amplify the power of their minds, and the lattices sound similar to silicon lattices. Knowing something about science enhances my enjoyment of science fiction, and reading science fiction enhances my enjoyment of science!