The combined effects of anodization parameters on morphological of the porous silicon and the ballistic electron emission of PS-based emitter

A new research strategy that fixed the anodic electrical charge was proposed to investigate the combined effects of the anodization current density and anodization time on the porous silicon (PS) morphology and the cold emission properties. The microstructure of the PS was characterized by atomic force microscope and scanning electron microscope, and the electrical performance of the PS-based emitter was measured in vacuum. The experiment results show that the anodization current density is an outstanding parameter in controlling the PS morphology and emission characteristics than etching time. The electron emission measurement results demonstrate that 15 mA/cm2 is an effective etching current density to improve the performance of the PS emitter at a fixed anodic electrical charge Q = 60 mA min. A modified quasi-ballistic electron drift model proposed in this work further demonstrated that PS layer including more silicon nanocrystallites with favorable interconnected property can significantly improve the field emission property since it could provide more and stable accelerating tunnels for electrons during the device operation. This work is helpful to clarify the combined role of the key anodization parameters on the PS micromorphology and also contribute to the fundamental understanding of the field emission mechanism of PS-based emitter.