New insights in high-energy electron emission and underlying transport physics of nanocrystalline Si

This paper presents quantitative analysis of electron emission from nanocrystalline Si dots, and discusses its mechanism based on the calculations of electronic and phononic states. Analysis of emission energy distribution measured from the vacuum level shows that the energy at the peak of the distribution increases linearly with increasing voltage applied across the nanocrystalline Si system. The slope of the linear law is unity, regardless of process conditions. Increasing voltage significantly changes the shape of the distribution at the energies smaller than the peak, while it has minimal impact at the energies larger than the peak. Both the conventional field emission model and the metal-oxide-semiconductor model fail to explain those behaviors. Calculations of electronic and phononic states in a chain of the nanocrystalline Si dots indicate a possibility of strong suppression of electron energy relaxation, which may be a possible mechanism of the high-energy electron emission phenomena.