As I increase my doping concentration my band gap tends to increase . Kindly explain?.
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Increase the band gap of a low band gap semiconductor by alloying it with a higher band gap semiconductor. For example, increasing the percentage of Al in GaAs to form AlGaAs increases GaAs band gap towards thata of AlAs. This is no longer termed as doping because the concentration of the added impurity (Al here) is much higher (few parts per hundred).
In the case of heavily doped n-type semiconductors Fermi level can be located in conduction band Ec+dE (strong degenerated semiconductors). In this case the optical transitions of electrons from valance band can take place only to the energy levels in conduction band located above the Fermi level, since energy levels below the Fermi level are filled with electrons (figure). Therefore, the location of the self-absorption edge shifts toward higher energy and thus the effective optical band gap is equal to Eg+dE. This is the Burstein-Moss effect.
I agree with above answers and also it depends on the dopant ionic radius.
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the bandgap of the material mainly depend on the following factors; thickness of the thin film , grain size , and temperature. When temperature increases, the amplitude of atomic vibrations increase, leading to larger interatomic spacing. The interaction between the lattice phonons and the free electrons and holes will also affect the band gap a little .
The band gap of a material depends on a number of factors. We observed a similar phenomenon when Ag2O was doped with Zn. One possible reason can be the presence of the orbitals of the dopant atom in the VB or CB. This leads to hybridization with the existing orbitals and results in shifting of the energy levels. Studying the DOS plots from DFT calculations led us to the above conclusion. Hope this helps.
Article Zn doping induced band gap widening of Ag2O nanoparticles
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