Ti₃C₂ (MXene) based field electron emitters

Abstract

As a novel class of two-dimensional materials, MXene has provoked tremendous progress for various applications in functional devices. Here, we pioneer a preliminary understanding on the field emission behavior of MXene for the first time. Ti3C2 paper is fabricated by using facile filtration method, and multiple vertical sheets appear on the surface of MXene paper with high electrical conductivity (2.93 × 105 S m−1) and low work function (3.77 eV). The field electron emission performance and electric field distribution on MXene emitters are measured and simulated under planar and standing conditions. Both emitter conditions exhibit stable, uniform electron emission pattern, and the standing emitter achieves high emission current density of 59 mA cm−2 under 7.5 V μm−1. This work demonstrates the feasibility of MXene as cold electron source, establishing a preliminary foundation for its applications in field emission-based devices.

Comparative Study of Cold Electron Emission from 2D Ti3C2TX MXene Nanosheets with Respect to Its Precursor Ti3SiC2 MAX Phase

“…In this context, Chen et al first examined the FE behavior of Ti 3 C 2 MXene paper and obtained a turn-on field of 7.6 V μm −1 at a current density of 0.1 mA cm −2 . 37 Following this, an improvement in the FE characteristics of a Ti 3 C 2 T X MXene via plasma treatment has been reported by Hong et al 38 It has been observed that the H 2 -plasma-treated MXene thin film emitter displayed a turn-on field of 8.5 V μm −1 . Wu et al reported excellent field emission properties of the MXene that was fabricated by etching of the Al layer from Ti 3 AlC 2 .…”

“…In addition to the aforementioned applications, like the layered 2-D materials, MXenes have attracted the attention of field emission researchers. In this context, Chen et al first examined the FE behavior of Ti 3 C 2 MXene paper and obtained a turn-on field of 7.6 V μm –1 at a current density of 0.1 mA cm –2 . Following this, an improvement in the FE characteristics of a Ti 3 C 2 T X MXene via plasma treatment has been reported by Hong et al It has been observed that the H 2 -plasma-treated MXene thin film emitter displayed a turn-on field of 8.5 V μm –1 .…”

Electrical Conductivity Enhancement and Electronic Applications of 2D Ti3C2Tx MXene Materials

“…Although Ti 3 C 2 T x with good conductivity in some electronic devices is widely studied in research, such as supercapacitors, [ 22 ] metal ion batteries, [ 104 ] sensors, [ 25 ] and so on. Nevertheless, only a small amount of work reports the application of Ti 3 C 2 T x MXene on vacuum electronic devices or semiconductor electronic devices such as field emission devices, [ 14c,27 ] transistors, [ 107a ] triboelectric nanogenerators (TENG), [ 90,109 ] and so on, all of which still requires lots of research efforts to implement them.…”

“…Currently, MXene is widely used in capacitive de‐ionization, [ 19 ] electromagnetic interference, [ 20 ] metal ion batteries, [ 21 ] supercapacitors, [ 22 ] transparent conductors, [ 23 ] electrocatalysis and photocatalysis, [ 24 ] gas sensors and biosensors, [ 25 ] thermoelectric materials, [ 26 ] and many other aspects. [ 27 ] Prospectively, MXene has extraordinary electronic applications because of its excellent electrical conductivity. Therefore, improving the electrical conductivity of MXene has become a major difficulty in current researches, and thus a research hotspot.…”

“…e) Vacuum assisted filtration. Reproduced with permission [27]. Copyright 2020, IOP Publishing Ltd. f) Blade-coating process.…”