Carrier movement and concentration Flashcards
What is drift current?
current caused by an external electric field, where charge carriers (electrons and holes) move based on their charge.
What is diffusion current?
current arising from a non-uniform distribution of charge carriers, leading them to move from regions of high concentration to low concentration.
What is carrier density/concentration?
The number of charge carriers (electrons or holes) per unit volume.
Why is current density preferred over current?
current density is independent of the material’s geometry
What are the formulae for current density J?
J=I/A, J=-qnv
How do we figure out the amount of current flowing in a semiconductor?
we need to know the Density of States, and the Fermi-Dirac probability function
What is the Fermi-Dirac function?
the probability of finding an electron in an energy state
What is the Density of States?
the number of available quantum states per unit volume per unit energy in an energy band.
