Low Temperature Synthesis of Lithium-Doped Nanocrystalline Diamond Films with Enhanced Field Electron Emission Properties.

Kamatchi Sankaran,Ping-Yen Hsieh,Jeong Park,Paulius Pobedinskas,Kalpataru Panda,I-Nan Lin,Nyan-Hwa Tai,Ken Haenen,Marlies Van Bael

doi:10.3390/nano8090653

Abstract

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.

Highlights

Nanocrystalline diamond (NCD) films grown by chemical vapor deposition, possessing unique and advantageous properties such as high hardness, high chemical inertness, and negative electron affinity (NEA), can be a good candidate for device applications [1,2]
The F-N plot in the inset I of Figure 1 shows that the β value of the nanocrystalline diamond (NCD)/Cr/LNO films is βNCD/Cr/LNO = 1670, whereas the inset of Figure S1a in the supplementary information indicates that the β-value of NCD films is βNCD/Cr/Si = 980, revealing a larger field enhancement factor value for the NCD/Cr/LNO films
The results described above indicate that the utilization of a Cr interlayer and incorporation of Li in NCD films fulfill these two critical requirements simultaneously, such that NCD/Cr/LNO films show a low bulk/interfacial resistivity leading to enhanced field electron emission (FEE) properties

Summary

Introduction

Nanocrystalline diamond (NCD) films grown by chemical vapor deposition, possessing unique and advantageous properties such as high hardness, high chemical inertness, and negative electron affinity (NEA), can be a good candidate for device applications [1,2]. Despite these marvelous properties, the absence of highly conducting NCD confines the potential for the use of this material in electron emission devices. A high-substrate growth temperature of above 800 ◦C is required to stimulate the n-type doping process, especially when nitrogen and phosphorus are used as dopants [4,5,6], which is not well-suited for the device fabrication processes. Fabrication of highly conducting n-type NCD films at low temperature are desired for the development of diamond-based electronics

Methods

Results

Conclusion