Engitek.com

All  Engineering and Technology Information in One Place.....

Home

About This Site

Sections  Directory

Search This Site

Privacy Policy

Tired of looking for a job?, Cansado de buscar trabajo?

 

 

content

 

Semiconductors Devices

 

Electronics Technology Information Sites

 

Science and Tech Forum

 

Electronics Engineering Information by Categories

 

Engineering and Science Software

 

Free Science-Tek Magazines and Publications

 

Regulatory Offices and Agencies and Standards

 

Patents  Information

 

Prototypes Developing Houses, Devices and Tools

 

IC’s Foundries  and IC Development Services

 

Certification Labs

 

Operation Manuals

 

Physics Units Converter Calculators

Convert any type of unit into any other of any system or scale

 

Alternative Energies Tutorials:

Biofuels

Ocean Energy

Wind Energy

Solar Energy

Geothermal

 

Lean Manufacturing Tutorials:

The Seven Causes of Waste

The 5S

The 5 Whys

The 4 M’s +1

Cause Effect / Fish Diagram  

The 4W’s +H+W

DMAIC

FMEA

Project Charter Example

Value Stream Mapping Introduction and Icons

Current or Present State Map

Future Sate Mapping

Cell Production

Kanban Production System

 

EarthquakesTutorials

 

Electronics and Electromechanical Distributors

 

Jobs Portal

Easily find your dream Job

 

Technology News

 

Science News

 

Business News

 

Electronics, RF and Communication Concepts

Rsistors and capacitors colors code

The Logarithm

The bel, decibel , the dbm and the dbmv

Electrical noise definition and Thermal noise

Signal to noise ratio

Physical Constants

 

Electronic Warfare and Radar Systems Engineering Handbook

Search this site

Para nuestros amigos de habla hispana, los invitamos a visitar el portal tecnológico en español:

www.industriaytecnologia.com

 

If you likes this site, please check like and share above:

To share this site:

To share this page:

If you don’t see the page information, remove the advertising above by clicking on the x on the upper right side of it

Solar cells, Photovoltaic Principles, Semiconductors materials n and p

 

<< Continue from previous page

 

Extrinsic Materials Type n and p

To create practical electronic components two types of materials must be prepared from a base of a pure intrinsic semiconductors, such materials are type n (negative) and type p (positive), these materials are the base of all semiconductor devices industry, including solar cells.

 

Material Type n

Materials type n are created by adding a controlled number of impurities atoms to the semiconductors. On semiconductors materials type n elements with 5 valence electrons or pentavalent such as Antimony (Sb), Arsenic (As) or Phosphorus (P) are added, these types of elements are called electron donors or just donors. The additions of these elements create a surplus electron in each atom that has no covalent bond in the crystal lattice, it is very weakly attached to the parent atom easing the moving of the electron in the new doped material n. The preferred  doping element for materials type n on solar cells is Phosphorus.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Materials Type p

Materials type p are formed by adding atoms with only 3 valence electrons such as the Boron (b), Gallium (Ga)  or Indium (In)  as a mean to create a electron deficit in the covalence bond with the Silicon atoms, this deficit of electrons creates a positive charge or hole in the semiconductor material, these types of elements are called electron acceptors or just acceptors, the preferred doping element for material type p on solar cells is Boron.      

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Solar Cell Operation:

(Refer to figure here >>)

It was learned that the solar cells are formed by two types of semiconductor materials p and n, it was also learned that to increase the efficiency of the solar cells to a practical level some small percent of impurities of other elements are added to increase the majority carriers and conductivity.

 

On the n side of the junction just in the border there are very few free electrons  and in the p side just in the junction border are very few holes or positive charges, these majority carriers attract each other producing a “neutral zone” where no more positive or negative charge carriers will exist, after all the majority carrier have been neutralized each other in the junction boundary a electrostatic field is formed, the impurity elements donors now have lost their electrons and become positive, while acceptors have lost their holes and now become negative, due to these loses the atoms are now electrically charged and are called ions.

 

As seen on the figure when a photon hits the n material, an electron is displaced making that atom positive, other electron in the lattice immediately tray to fill that hole, now  the atom that provided the electron will have a new hole to fill, this behavior starts a chain reaction in which the hole is moving trough the atoms in the material until no more holes are available, once all holes have been “used” in the n material, the electrons on the p side will fill the holes trough the barrier which has a potential between 0.4 to 0.7 volts, this complete the electrical circuit started by the photon.

 

Continue on next page >>