3 part 1

the heart of solid state rectifier, which is usually a piece of crystalline silicon

silicon contains _ valence electrons

the _ must lose or gain energy to move from one energy level to another

electrons in the _ (which corresponds to the unfilled energy levels) are relatively free from atomic bonding and may move freely through the semiconductor material

if there is no forbidden region at normal temperature and pressure, the material is called a _

if the forbidden region is in the order of 1 electron volt, the material is _

if the forbidden gap is of the over 10 eV, the material is _

at absolute 0 temperature, the semiconductor behaves as _

at _ _, some of the electrons are thermally raised to the conduction band and are availabe to support current

silicon containns four valence electrons. if a material with five valence electrons is added as an impurity to the silicon crystal, the added atoms will take the place of some silicon atoms throughout the crystal

the impurity in N-type semiconductor is called _ since it donates an extra electron

the crystal resulting from the addition of the donor is called the _, derived from the _ charge of the surplus electrons

N-type semiconductors:

is an impurity with only three valence electrons is added to silicon, the impurity atom will have only three electrons to share with four surrounding silicon atoms

in P-type semiconductor, the absence of the electron is called a _

since the hole is a _ particle, the material is called P-type

P-type semiconductors:

can be formed only by a complex process in which the P and N materials are diffused into a single crystal

when electrons leave the n-type material, the junction area is left with a net positive charge. similarly, the p-type material acquires a negative charge. this creates what is called _

has a junction potential that is opposite in sign to the designation of the materials