scholarly journals Improved Field Electron Emission Properties of Phosphorus and Nitrogen Co-Doped Nanocrystalline Diamond Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1024 ◽  
Author(s):  
Fernando Lloret ◽  
Kamatchi Jothiramalingam Sankaran ◽  
Josué Millan-Barba ◽  
Derese Desta ◽  
Rozita Rouzbahani ◽  
...  

Nanocrystalline diamond (NCD) field emitters have attracted significant interest for vacuum microelectronics applications. This work presents an approach to enhance the field electron emission (FEE) properties of NCD films by co-doping phosphorus (P) and nitrogen (N) using microwave plasma-enhanced chemical vapor deposition. While the methane (CH4) and P concentrations are kept constant, the N2 concentration is varied from 0.2% to 2% and supplemented by H2. The composition of the gas mixture is tracked in situ by optical emission spectroscopy. Scanning electron microscopy, atomic force microscopy (AFM), transmission electron microscopy, and Raman spectroscopy are used to provide evidence of the changes in crystal morphology, surface roughness, microstructure, and crystalline quality of the different NCD samples. The FEE results display that the 2% N2 concentration sample had the best FEE properties, viz. the lowest turn-on field value of 14.3 V/µm and the highest current value of 2.7 µA at an applied field of 73.0 V/µm. Conductive AFM studies reveal that the 2% N2 concentration NCD sample showed more emission sites, both from the diamond grains and the grain boundaries surrounding them. While phosphorus doping increased the electrical conductivity of the diamond grains, the incorporation of N2 during growth facilitated the formation of nano-graphitic grain boundary phases that provide conducting pathways for the electrons, thereby improving the FEE properties for the 2% N2 concentrated NCD films.

2010 ◽  
Vol 152-153 ◽  
pp. 413-417
Author(s):  
You Sheng Zou ◽  
Zheng Xue Li ◽  
Hao Yang

The boron-doped nanocrystalline diamond films were prepared on Si(100) substrates by microwave plasma chemical vapor deposition in gas mixture of CH4/H2/trimethylboron (TMB) with B/C ratio in the range of 0-1900ppm. The dependencies of surface morphology, microstructure, phase composition and field electron emission properties on the B/C ratio were systematically investigated by scanning electron microscope, X-ray diffractometer, visible and UV Raman spectroscopy. The results show that the diamond grains gather together forming ball-like clusters with inhomogeneous size, the doped boron atoms can promote the growth of plane (111) surface and terminate the diamond growth sites, resulting in the reduction of growth rate with the increase of B/C ratio in the gas mixture. The two peaks located at approximately 500 and 1220cm-1 resulted from Fano interference were observed in the visible Raman spectra for the heavily boron-doped nanocrystalline diamond film, and the sp2/sp3 ratio of carbon bonds increased with B/C ratio increasing in gas mixture. The field electron emission performances of the boron-doped nanocrystalline diamond films were obviously dependent on B/C ratio in the gas mixture, and boron doping can improve their field electron emission properties remarkably. The low turn-on electric field of 7.6V/μm was achieved for the boron-doped nanocrystalline diamond film deposited at B/C ratio of 1900ppm.


Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 653 ◽  
Author(s):  
Kamatchi Sankaran ◽  
Kalpataru Panda ◽  
Ping-Yen Hsieh ◽  
Paulius Pobedinskas ◽  
Jeong Park ◽  
...  

Low temperature (350 °C) grown conductive nanocrystalline diamond (NCD) films were realized by lithium diffusion from Cr-coated lithium niobate substrates (Cr/LNO). The NCD/Cr/LNO films showed a low resistivity of 0.01 Ω·cm and excellent field electron emission characteristics, viz. a low turn-on field of 2.3 V/µm, a high-current density of 11.0 mA/cm2 (at 4.9 V/m), a large field enhancement factor of 1670, and a life-time stability of 445 min (at 3.0 mA/cm2). The low temperature deposition process combined with the excellent electrical characteristics offers a new prospective for applications based on temperature sensitive materials.


2003 ◽  
Vol 48 (18) ◽  
pp. 1934-1937 ◽  
Author(s):  
Rangqi Cai ◽  
Guanghua Chen ◽  
Xuemei Song ◽  
Guangjian Xing ◽  
Zhenjian Feng ◽  
...  

2020 ◽  
Vol 15 (2) ◽  
pp. 276-283 ◽  
Author(s):  
Junqi Xu ◽  
Yanrui Wang ◽  
Wenjie Wang ◽  
Zijun Xu ◽  
Yonglei Jia ◽  
...  

Large-scale PrB6 nanowires were fabricated by an effective, catalyst-free, and a simple low-pressure chemical vapor deposition (LPCVD) process. These nanowires, characterized in detail by various analytical instruments, demonstrated the large aspect ratio and high single-crystalline grown along the [001] crystal direction perpendicular to the (001) crystal plane. The field electron emission equipment tests manifest that the asgrown PrB6 products have a low turn-on field (Eto, 2.32 V/μm), a threshold field (Ethr, 4.28 V/μm), a high field enhancement factor (β, 2336), as well as a stable current-density (J) of field-emission. The relationships of the field electron emission parameters, such as J, Eto, and β versus cathode gap (d), have been established when d is increased from 500 μm to 800 μm. The outstanding properties suggest that the PrB6 products may be promising emitters in the cold-field-emission cathode application.


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