Plasma Post‐Treatment Process‐Induced Grain Coalescence to Improve the Electron Field‐Emission Properties of Ultrananocrystalline Diamond Films. Issue 23 (28th October 2022)

• Record Type: Journal Article
• Authors: Chen, Chengke; He, Zhi; Chen, Wei-En; Yeh, Chien-Ray; Lin, Chii-Ruey; Leou, Keh-Chyang; Lin, I-Nan; Hu, Xiaojun
• Is Part Of: Physica status solidi. Volume 219:Issue 23(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-28
• Subjects: chemical vapor deposition -- electron field emission -- nanocrystalline diamonds -- plasma; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202200362
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Plasma post‐treatment (PPT) process is an effective way to improve the electron field‐emission (EFE) properties of microwave plasma chemical vapor deposited ultrananocrystalline diamond (MP‐UNCD) films, while its effects on hot‐filament chemical vapor deposited UNCD (HF‐UNCD) films were not confirmed. Due to monodispersed Ta atoms existing in HF‐UNCD films, PPT process shows different effects on the structure evolution and EFE properties of HF‐UNCD films and MP‐UNCD films. CH4 /N2 PPT process make diamond grains change from small spherical particles to large plate‐like aggregates with lots of stacking faults in HF‐UNCD films. This is ascribed to both the CN species in CH4 /N2 plasma, which induces anisotropic growth of diamond and the monodispersed Ta atoms resulted in transition of graphite to diamond, which connect the neighboring nanosized diamond grains to a larger one and produce lots of stacking faults. The charges are easier to accumulate and emitted in the edges of the plate‐like diamond and stacking faults have lower negative electron affinity. These lower the turn‐on field from 26.3 to 12.7 V μm −1 . It is different from that of MP‐UNCD films, in which only anisotropic growth occurs and forms needle‐like diamond due to CN species. Abstract : The electron field‐emission properties of ultrananocrystalline diamond films (UNCD) prepared by hot filament chemical vapor deposition (HF‐CVD) can be improved by CH4 /N2 plasma treatment, which is ascribed to the formation of plate‐like diamond with lots of stacking faults rather than needle‐like diamond surrounded by graphite that forms in UNCD prepared by MP‐CVD. Ta atoms vaporized from hot filament result in different microstructure evolution.