A crucial tool for analysis and design of semiconductor devices is energy band diagram. Understand theuse of such band energy diagram is very important. Answer following questions about energy band-diagrams

What is a band diagram in relation to semiconductor materials? Draw a typical band-diagram for a semiconductor material and mark the position of conduction-band, valence band and the bandgap. Why do crystal lattice (such as Si lattice) have bands of energy, while isolated Si-atoms do not have such bands? We know that electrons and holes that are responsible for conduction. But where are these located in this bands? Which direction energy of an electron increase along the y-axis of the band diagram? Energy of a hole?