In inorganic phosphor papers we are usually using the term activator doping (sometimes activator doping percentage can be around 30% or more). Is it actually doping or substitution?
Doping comes from the semiconductors science. In this case, very small quantities
allow modifying signficiantly the electrical properties.
Substitution is the word used when replacing one element by another one at levels reaching several %.
We sometimes teach to student that they should say susbtitution instead of doping when dealing with high doping/substitution rate BUT the word doping is now so widely used in the scientifici community that it does not really matter.
i should add that by extension we also employ "acceptor doping" and "donor doping" in oxides even if the result is sometimes very different from one is observed in semiconductors since the compensating charge is for instance an oxygen vacany (in case of acceptor doping).
If I may add, doping is introducing a foreign material to another substance; it presence could bring about re-structuring of the original substance. But in substitution, generally, an incoming molecule is introduced to replace some part of another substance. Here, one material must be going in and then another one going out. But in doping, some part of the material to be doped must not necessarily be replaced.
Doping comes from the semiconductors science. In this case, very small quantities
allow modifying signficiantly the electrical properties.
Substitution is the word used when replacing one element by another one at levels reaching several %.
We sometimes teach to student that they should say susbtitution instead of doping when dealing with high doping/substitution rate BUT the word doping is now so widely used in the scientifici community that it does not really matter.
i should add that by extension we also employ "acceptor doping" and "donor doping" in oxides even if the result is sometimes very different from one is observed in semiconductors since the compensating charge is for instance an oxygen vacany (in case of acceptor doping).
This concept is also used for conducting polimers when neutral pristine polymers are doped (oxidized or reduced) in orden to became a conductor o semiconductor material.
As Dezaneau said, doping is from semiconductor science, where as generally substitution is from metallurgy / organic chemistry etc. In general doping is mostly used for inorganic oxide materials and extending to molecular electronics. where as Substitution is more general - a) substitution reactions, where one of the functional group can be replaced with another in organic reactions, b) Substitional solid solutions in case of alloys etc.
Doping generally refers to a very small addition, say less than 1%. Substitution is in much higher concentration and the added constituent is meant to substitute for the existing atom or ion. In the case of doping one is not sure about the position of the dopant. It could be a defect.
Doping is a specific term used for introducing some defect in a “HOST
NONSTOICHIOMETRIC CRYSTAL” by incorporating an infinitesimally small amount
of some “foreign” substance which occupies only the INTERSTITIAL sites but never the
CONSTITUENT sites and may change the electronic/ conducting/ mechanical/ magnetic /thermal properties of the crystal.
On the other hand, substitution is a general term applied to all phases (solids/ liquids/ gases)
But the “foreign” substance (in any permissible amount) always occupies the CONSTITUENT sites and never the INTERSTITIAL sites.
substitution is an atomic interchange
doping should be a substitution and or interstitial doping
Hi,
The two words refer to different electrical situations.
- A doping atom changes the electrical properties of the doped material. Adding less than 1% of boron or phosphorus to pure (resistive) silicon dramattically changes its conductivity. Phosphorus induces electron conduction (n type), boron induces hole conduction (p type).
- Substitution does not change the electrical properties of a material. For example Ga As can be mixed (alloyed) in any proportion with AlAs by substituting gallium with aluminum. This substitution does not change the electrical properties of the mixture.
I think that "doping'' and "substitution" are general terms and do not necessarily used for modifying electrical properties only. Their effect can be in any physical or chemical properties.
Doping of crystals means an introduction of impurity (foreign) atoms which usually substitute cation or anion sites. More rarely they are at interstitials. If the solubility of impurity atoms is small the band gap of crystals remains unchanged. In this case we only say about the doping of crystals by impurity atoms. Other impurity atoms can have large solubility. In this case the substitution of cation or anion sites also takes place. However, large concentration of impurity (foreign) atoms induces the formation of alloys (or substitutional solid solutions). Therefore such impurity atoms became one of components of these alloys. The band gap of alloys is changed in comparison with main compound. Of course, the introduction of 30% impurity atoms reflects the formation of substitutional solid solution.
The site of substitution should may definite, but sometimes the site of dopping may be unclear
As far as I know ,Doping is classified as substitution doping (whatever cationic or anionic) and interstitial doping . So Substitution is nothing but substitution doping.
Doping means adding something in a very small quantity. Substitution is replacement through chemical reaction.
Doping is normally a physical reaction and only take place on the surface of the metal.
Substitution is the word used when replacing one element by another one at levels reaching several %
substitution is an atomic interchange, and for stable structure you need change atoms no more than +- 15% of difference in their ionic radius (according to Prewitt and Shanon effective ionic radius)
doping could be a substitution or an interstitial doping or both
In the formula SrFexTi1-xO3 (if x= .05 to .40), what would be best suited terminology (doping / substituted). A minor phase develops at x=.20.
Doping and Substitution are completely different terms.
1. Doping means a very small number of additives used for modification. Some time MnO2 or Mn2O3 are used in bismuth ferrite based materils to modify certian properties, so in formula, it can be written as
SrFeO3+xMnO2 or Mn2O3.
2. While substitution is the replacement of one constituent on the other which can be written as
Bi(1-x)SmxFeO3 or SrTi(1-x)FexO3 actually it is a trand that the element which is substituted written after that which is substituted.
3. A solid solution is actually the replacement of one unit cell on the other. In material engineering when one Perovskite unit cell is replaced by the other one is called solid solution. The solid solution may be binary, ternary or quarternary. In formula it can be written (1-x)BiFeO3-xBaTiO3, in case of ternary like
(1-y){(1-x)BiFeO3-xBaTiO3}-ySmFeO3 and so on.
Dear Vandna Luthra the best word I recomend for you is substitution or modification not doping.
Thanks Dr. Muhammad. That is totally agreeable. But in plenty of papers, doping is widely used. In literature, in most of the papers on Strontium titanate with very high levels of Fe, 'doping' has been most generally instead of 'substitution'.
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