Hello,
I can't seem to understand what HOMO and LUMO levels are and how they are related to semiconductors.
I have an idea in my head but I don't know if it's any good, I would really appreciate if someone could confirm or bust it:
Every molecule has orbitals which describe the likelihood of an electron beeing there. There can be multiple orbitals for each atom and each bond. Lets say there are 5 different orbitals (a,b,c,d,f) in one bond, but only 3 electrons. "Normaly" all the electrons are in a,b and c. But under certain conditions, some electrons can jump to a higher level, creating a unoccupied orbital. Lets say the electrons are in a,b and d now. Therefore level c is Lumo (lowest unoccupied molecular orbital) and level d is homo (highest occupied molecular orbital). But this distribution is not constant over time, so the electrons can jump to different orbitals and can even jump from one atomic bond to the next, therefor creating a current flow. With this behaviour electrons can even jump inbetween orbitals from different molecules. You can inrease the likelihood of exsisting Lumo and Homo states by doping the material with atoms or molecules that have to many or too few electrons. You can also increase the likelyhood by applying an electric field ("switching the transistor on").
Is this explination correct, or is it complete bullshit? 
I also wonder how a potential question for this topic would look like.
Greetings,
Leo