How to study Alloying and Doping

A- Definitions:

First of all  we attempt to clarify  approximately the difference between alloying and doping despite the fact that the difference is still ambiguous.

1- In alloying, the introduction of an external element  is done with a big concentration (for example, more than 10%  ), but in doping the concentration is very little (for example, less than 10%  ).

2- In alloying, the crystal structure is usually kept what's not always true for the doping.

3- In alloying, we can use any machine, but in doping we need to use a strong machine (computing station or a cluster).

B- Study 

Since there are 2 ways of alloying, we will take the example of alloying by subtitution.

Here we illustrate how to study the alloying and we take the example of the CdZnxTe1-x

We take the original compound CdTe with its crystal structure and lattice parameters:

Crystal structure	Zinc blende
Space group	F43m
Lattice constant	a = 6,48 A

Cd (4a) : 0,0,0
Te (4c) : 1/4,1/4,1/4

There are 4 atoms of Cd and 4 atoms of Te in the unit cell and all of the 4 atoms of Te are inside the unit cell.

case 01: We replace 1 atom of Te by 1 atom of Zn
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CdZn0.25Te0.75

case 02: We replace 2 atoms of Te by 2 atoms of Zn
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CdZn0.5Te0.5

case 03: We replace 3 atoms of Te by 3 atoms of Zn
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CdZn0.75Te0.25

case 04: We replace 4 atoms of Te by 4 atoms of Zn
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CdZn 

NOTE: To calculate the lattice parameters of an alloy we have to use the Vegard law (check this link http://materials-sciences-algerien1970.blogspot.com/2017/07/vegards-law-from-wikipedia.html ).