Tuning the field emission and electronic properties of silicon nanocones by Al and P doping: DFT studies.

The effect of replacing an Si atom of a silicon nanocone (SiNC) by Al or P atom on its electronic and field emission properties was investigated using density functional theory calculations. Molecular electrostatic potential surface indicates that the electrons do not spread out on the surface of SiNC evenly, and they tend to accumulate more at the apex, facilitating the electron emission from this site. Replacing an Si atom of the apex of nanocone by Al and P atoms is energetically more favorable than that of the wall by about 12.0 and 8.8 kcal/mol, respectively. Both Al- and P-doping processes increase the SiNC electrical conductivity, but the electron emission from the surface of SiNC increases after the P-doping and decreases by Al- doping. The electron emission in the P-doped SiNC is predicted to be about 600 times greater than that of the pristine SiNC at room temperature. The Al- or P-doping makes the SiNC a p-type or n-type semiconductor.