Spectral weight shift in the valence band density of states and concurrent increase in field emission by hydrogenation of FeCo-SiO2 nanocomposites

Debalaya Sarker, S. Ghosh, P. Srivastava

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Hydrogenated and roughened surfaces of hydrogen plasma treated (HPT) FeCo-SiO2 nanogranular films are found to be efficient field emitters in comparison to their as-grown and furnace annealed counterparts. Partial etching using hydrogen plasma roughens the surface and improves the field emission by enhancing the local electric field at the protrusion tips. A layer of Feδ+-Hδ- dipoles over the roughened HPT film surface and enhanced defects are likely to make the composite surface more emission-active by reducing the overall work function. The reconstruction of the electronic structure is mainly attributed to the Fe2+ to Fe3+ conversion and the appearance of anti-bonding states. Further, hydrogen-induced volume expansion of FeCo particles improves the conductivity. Thus tunnelling of electrons from the valence band becomes easier via these inter-gap anti-bonding states. The agglomeration of nanoparticles, out-diffusion of hydrogen, and further etching of the film at a higher substrate temperature of the plasma treated films reduces the FE current density drastically.

Original languageEnglish
Pages (from-to)63377-63381
Number of pages5
JournalRSC Advances
Volume5
Issue number78
DOIs
Publication statusPublished - 2015
Externally publishedYes

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