Why semiconducting nano-material's properties are highly dependent on density of the surface states than that of doping level ?
And how doping and density of surface states can be separated, when there is combined effect?
The determining factor is that for small nanoparticles is a large ratio between the number of atoms located at the surface and in the bulk. Therefore, usually there is a large density of surface states, which will affect on the physical properties of nanoparticles. The doping level of small nanoparticles, when impurity atoms are in their volume, is insignificant. The first step in the separation of contributions of surface states and doping is study undoped and doped nanoparticles. However, this problem is not simple, since the density of surface states can be changed by doping.
The determining factor is that for small nanoparticles is a large ratio between the number of atoms located at the surface and in the bulk. Therefore, usually there is a large density of surface states, which will affect on the physical properties of nanoparticles. The doping level of small nanoparticles, when impurity atoms are in their volume, is insignificant. The first step in the separation of contributions of surface states and doping is study undoped and doped nanoparticles. However, this problem is not simple, since the density of surface states can be changed by doping.
Yes you are right. Is their any model or specific calculation to differentiate between doping level and density of surface states for electrical and optical properties.
Unfortunately, I can not say whether there is any theoretical works on this issue.
I would also note that for nanoparticle based on A2B6 group semiconductors there is a high solubility transition metal atoms. Therefore, at low concentrations of atoms it comes to doping, while large (more than 0.1 atomic percent) are dealing with solid solutions known as diluted magnetic semiconductors. Here, there is a strong effect of transition metal atoms on the surface states of nanoparticles. An example of this would be a paper that is attached.
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