How transistors work and how graphene can be used in transistors.

Transistors are a device made of semiconductors to alternating current to direct current or to amplify a weak current. The word is a made-up word of TRANSfer varISTOR. Before transistors were invented, people used a vacuum tube, which applied the Edison effect (Edison's one and only scientific contribution). Thomas Edison found that electrical current gets transported not only by a wire but also by vacuum or a gas medium. 

The material that makes semiconductors is usually silicon. Pure silicon has 4 valence elctrons which makes one silicon atom form a crystal structure with 4 different atoms. This makes a tetrahedral structure; thus, the smallest unit of the silicon semiconductor is a tetrahedral. Silicon is less conductive than metals (we don't want the electronics to carry the current all the time) but more conductive than insulators which do not conduct electricity. 

To improve the current conductance in transistors, "doping" is done. Doping means replacing one atom from a tetrahedral structure of silicon with another atom. How doping improves the electron transfer will be further explained. This doping method generates two different types of semiconductors: p-type and n-type. 
        
       n-type: If a silicon atom is replaced by phosphorous which has one more electron than the silicon. The extra electron in every unit of tetrahedral silicon-phosphorous structure initiates the current conductance by generating the electron flow, which is the current.  
   
       p-type: If a silicon atom is replaced by a boron atom which has one less electron than silicon, which creates a hole in the electron arrangement of the silicon-boron structure. These holes create space for the electrons to flow. 

The link to the information above: http://www.scribd.com/doc/156591914/Electrical-Conduction-Mechanism-in-Chemically-Derived-Graphene-Monolayers