In the process of doping in semiconductors:
1: How can a dopant atom take the place of a host atom in a crystal lattice? In fact, with what power can the dopant atom prevent the host atom from forming a bond with its other counterparts and establish a bond instead?
2: After the site of a host atom is occupied by a dopant, what happens to that host atom whose site is now occupied? In fact, where and in what new form does the fired host atom fit or establish a new bond? Should this driven host atom also take the place of another host atom? And is this process repeated sequentially? What then happens to the last ejected host atom?
1. This force is called entropy. The substitution of a lattice atom by a foreign atom increases the configurational entropy and, thereby, lowers the free energy of the material.
2. A substituted native atom can become interstitial or, in the process of diffusion, come to the surface and complete the crystal. It is possible that there are vacancies in the sublattice of replaced atoms, then their number will be reduced.
There are several different processes - impurities can be introduced during crystallization or by epitaxy or ion implantation or diffusion. Entropy is usually the driving force - but there are other energies and size matching to consider.
Dear Milad Fallah,
Doping refers to the intentional introduction of impurity atoms, known as dopants, into a crystal lattice of a material. Dopants are atoms of a different element from the host lattice material. The process of dopant atoms taking the place of host atoms in a crystal lattice is possible due to certain similarities in the electronic structure and size between the dopant and host atoms.
Here's how it generally works:
Overall, the successful incorporation of dopant atoms into a crystal lattice is a delicate balance of factors related to atomic size, electronic structure, charge balance, and material compatibility. These principles are essential for engineering materials with specific properties by carefully controlling the type and concentration of dopants introduced into the crystal lattice.
Dear Professors, Titov, Hanson and Mizrah,
Thank you so much for your response and the time you dedicated to me. And thank you for sharing your knowledge, which you have obtained with years of effort in the scientific path, to young people who are interested in science.
Respectfully,
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