Pentavalent Elements & Doping Semiconductors: Why Not 6 Valence Electrons?

[krishnenduk]

Doping doubt...

Why pentavalent elements are used in doping semiconductors why not an element with 6 valence electrons?

 

[kanato]

Here's a list of <a href="http://en.wikipedia.org/wiki/List_of_semiconductor_materials#Group_II-VI">II-VI semiconductors</a> where elements with 6 valence electrons are used.

Maybe someone who knows more about semiconductors specifically can answer your question, but my guess is that once you get to II-VI semiconductors the band gaps start to become large due to the stronger ionic character relative to III-V's. If the band gap is too large, you wind up with a good insulator or a bad semiconductor.

 

[charng]

Pentavalent elements are commonly used in doping semiconductors because they have five valence electrons, which allows them to easily bond with other elements and create impurities in the semiconductor material. These impurities, known as dopants, can either donate or accept extra electrons, creating either a surplus or a deficiency of electrons in the semiconductor, respectively. This process is crucial in creating the desired electrical properties in the semiconductor, such as conductivity and resistance.

On the other hand, elements with six valence electrons may not be as effective in doping semiconductors. This is because they have a full outer shell and are less likely to bond with other elements, making it more difficult to introduce impurities into the semiconductor material. Additionally, introducing a sixth valence electron can disrupt the delicate balance of the semiconductor's electrical properties, potentially rendering it unusable.

In summary, the use of pentavalent elements in doping semiconductors is a well-established and effective method in the field of semiconductor technology. While elements with six valence electrons may seem like a potential alternative, their full outer shell and potential disruption of the semiconductor's properties make them less practical for this purpose.