The pure silicon is doped with a group 3 element such as boron, aluminium or indium. These materials have atoms with three valence electrons (trivalent atoms). The three electrons will form covalent bonds with neighbouring silicon atoms. However there are not enough electrons to form the fourth covalent bond. This leaves a hole in the covalent bond structure and therefore a hole in the valence band of the energy level diagram. Every impurity atom will produce a hole in the valence band. These holes will drift to produce an electrical current if a voltage is applied to the material and the P type semiconductor is a much better conductor than the intrinsic pure silicon material.
- The silicon atoms form a square lattice
- The green atoms represent the donor atoms
- three of the four covalent bonds are formed with neighbouring silicon atoms
- The fourth bond cannot be formed as there are not enough electrons, this leaves a hole in the valence band
- Each donor atom produces a hole in the valence band
Note it is important to point out that the material is called P type semiconductor because the majority of charge carriers which contribute to an electrical current are positively charged holes produced by the doping process. There will be some contribution to the current flow from negatively charged electrons due to electron hole pair generation but these electrons are the minority charge carriers in this material. The P type material itself is not positively charged because the negative charge of the electrons of the donor atoms are balance by the positive charge in the nucleus.
Energy band diagram
The diagram below shows an energy band diagram for P type semiconductor. The valence band contains holes due to the incomplete covalent bond around each donor atom. The conduction band is empty as there are no free electrons.
Note this diagram does not show the electron hole pairs that would be present due to thermal energy. The electron hole pairs are minority charge carriers in P type semiconductors, the majority being the holes produced by the doping process.how london bridge fell what are the 5 stages of development how teaching happens why science of reading why entrepreneurs can't work for others whose work or who's work how startup funding works infographic what business can i start with 10k when product backlog retire why tech industry how company logos changed how many product managers does amazon have how much design for architect how many design principles are there which technology is not a form of broadband how much solution to put in contact case how much project managers make where design criteria how far phone from eyes which startup is best in india teaching where it matters how many technology be described as an element of ob what startup companies to invest in does development mean progress who owns businesses what products have titanium dioxide how system works why workers go on strike how many technology companies in the world how much management reserve who manufacturers how system restore where's device management on iphone which teaching jobs are in demand where is technology made which teaching jobs are in demand how much machine for ice cream whose an entrepreneur how management is multidimensional where are workers going where to manage icloud storage how many solution are there for equation log4 x 1 where startup folder windows 10 how many science regents are required to graduate how often company pay dividend who devised the contract with america when workers are asked to participate which technological advancement was most useful what start up business is successful when london stock market open from where manager derive performance expectation how startup funding works infographic what workers found in giant snake whose project is nlex how to know when the product was made why solution called mixture how much solution to put in hoover carpet cleaner why project management interview question how business taxes work where to solve programming problems when project price should be discussed how many teaching hospitals in the us how many science questions are on the act where to find device manager where tech companies are moving how many design styles are there how much product to use in wavy hair how much technology has china stolen how many system calls are there in linux how much products in amazon where is brooks from design star how much design house whose manager of salford city how much solution to drink for colonoscopy why equipment maintenance is important what business can i start with 10k what project is lil wayne from why solution called mixture who technology transfer pdf what company has the most employees how many design principles are there which tech companies are still hiring how science and religion work together who technology transfer guidelines what startup should i start from where to study science and technology for upsc who product specific guidance which project sekai character are you when solution is simple god is answering whom may concern startup where is izzy where to business listing who technology transfer how much solution in vax platinum where farm equipment is used where to eat london who system building blocks how much project engineer make who designs homes which science is the hardest how far answer which company was responsible for love canal where to go from teaching why entrepreneurs fail who entrepreneur for capitalist psychologist and economist whose project is 4ps when tech mahindra send offer letter whom definition whose products does ocado sell when science fell in love what company owns tiktok how many product owners per developer where do entrepreneurs work how teaching helps you learn how many products does amazon have how device driver where is brooks from design star what's the roadmap for lifting lockdown