Photoelectrochemistry

Type of semiconductor electrode

(a)  

The conduction and valence bands for metals are overlap, so the conduction band can be

• Not occupied

• Readily occupied

• Half occupied

• Never occupied

Example of pentavalent impurities

(a)  

N-type electrode is also known as (a)   due to each of atom of them donates one free electron crystal

The missing electrons is known as a

(a)  

The electrons in n-type electrode are the (a)   with regards to the number of free electrons required to fill the covalent bonds in the semiconductor

Example of trivalent impurities

(a)  

Formed when a trivalent impurity is added to pure semiconductor in a small amount

• N-type

• P-type

Band gap sufficiently large that electrons cannot be promoted from the valence band to the conduction band

• Metals

• Insulators

• Semiconductors

Band gap is not as large and electrons can be moved into the conduction band

• Metals

• Insulators

• Semiconductors