+1 ^
Also when your in a car stopped at a Red light.
if the person in front of you moves forward a little bit, leaving a gap
you would then also move forward to cover up the gape, and in the process you leave a gap where your car originally was stopped, then the person behind you would move into that gap and so on.....
Think of the cars as electrons and The gaps as holes !
and as each car (electron remember) moves forward it creates a current
[as current is the movement of charged particles]
This is the case of a P-type semiconductor (p stands for positive) as the holes produced are positively charged. A p-type semi-conductor is produced by doping silicon (semiconductor) with a group 3 element.
If you remember from year 10, an atoms outer shell can have 8 electrons. Semiconductors like silicon have 4 electrons in their outer shell, and too be complete they need to accept another 4 electrons.
However, once we dope a semiconductor with a group 3 element, which has 3 electrons in the outershell
we get 4 + 3 = 7
7 electrons in the P-type semiconductor outer shell. This makes it highly conductive as it only needs 1 more electron to accept to be complete.
You should know be able to understand the importance of doping, it is too increase the semiconductors conductivity.
N- type semiconductors (N stands for negative) is produced by doping Silicon with a group 5 element.
Which contains 5 electrons.
so, 5 + 4 = 9
9 electrons are present in the outer shell of a N-type Semiconductor,
So it needs to LOSE 1 electron to be complete.
Again, making the semiconductor highly conductive as 1 electron is easier to lose than 4 electrons.
Since the N-type semiconductor contains 1 more electron it is Negatively charged, as electrons have negative charges.
That should cover what you need to know about semi-conductors and doping in the syllabus.
Now you can read up on Diodes, and PN junctions
