the asymmetry encourages flows of electrons from the n-type material to the p-type material, setting up voltage and current

without the asymmetry, electrons cannot accept an incoming photon

the asymmetry encourages flows of electrons from the p-type material to the n-type material, setting up voltage and current

the asymmetry improves the efficiency of the cell by reducing reflectivity at the surface

P-type material is doped with a group V type material such as Phosphorous, and N-type material is doped with group III type material such as Boron.

N-type material is doped with a group III type material such as Phosphorous, and P-type material is doped with group V type material such as Boron.

N-type material is doped with a group V type material such as Phosphorous, and P-type material is doped with group III type material such as Boron.

N-type material is doped with a group V type material such as Boron and P-type material is doped with group III type material such as Phosphorous,.

It is better to have a large bandgap, as this allows for absorption of higher energy photons, and generates a large voltage in the PV cell.

It is better to have a smaller bandgap as then more electrons can be absorbed, and the alpha factor will be higher, meaning less material is required

The best option is to be part way between, so that the voltage can be high, the losses can be low, and the alpha factor isn't too bad.

Semi-conductor

Insulator

Conductor

Fermi level is the energy level of a photon that passes through a semiconductor without absorption.

The Fermi level is the likelihood that an electron will be in a higher energy state than the minimum energy level

The Fermi level is the energy difference between the valence band and the conduction band 

The Fermi level is the lowest energy the electrons in a crystal can obtain, when the material is at 0K

Electrons can be in any energy level depending on the energy level of the photon they have absorbed

There are 6 electrons, 2 of which are in the first energy level, and 4 are in the highest energy level, know as the valence shell.

There are 6 electrons in the valence shell, meaning carbon falls in group 6, the oxygen family.

The general chemical properties of an element can be shown by the group in which it occurs

The period table is how atoms know how to behave

The general chemical properties of elements can be shown by the period in which they occur

The atomic mass of an atom is determined by the number of electrons

The nucleus contain the electrons and protons of an atom

The nucleus is made up of neutrons and protons, and contains most of the mass of the atom