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

Abstract

Abstract-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.

Annealing effects on the operation stability of ballistic electron emission from electrochemically oxidized nanocrystalline silicon diodes

“…The importance of interfacial oxides between nc-Si dots for suppression of electron energy relaxation has also been supported by theoretical calculations of phonon modes and electron wave functions in the interconnected nc-Si chains. 15 Improvement of electron emission stability to a practical level would be attained by further suppression of interfacial defects.…”

Charge storage and electron/light emission properties of silicon nanocrystals

“…One of the reasons is that current injection into nc-Si causes a significant decrease in the internal quantum efficiency due to the interfacial oxide layer. To circumvent this problem, we propose a new high-energy electron emission approach which is unique to nc-Si dot array structures [17,23].…”

Operation of nanocrystalline silicon ballistic emitter in low vacuum and atmospheric pressures

“…The emission mechanism is based on a specific field-induced electron transport in the nc-Si layer: quasiballistic electrons are generated via multiple tunneling through a chain of nc-Si dots interconnected with thin oxide films [2][3][4][5] and are subsequently ejected into vacuum via tunneling through the top contact. The mean energy of emitted electrons extends to several electron volts.…”