Fast identification of the conduction-type of nanomaterials by field emission technique

Abstract

There are more or less dopants or defects existing in nanomaterials, so they usually have different conduct-types even for the same substrate. Therefore, fast identification of the conduction-type of nanomaterials is very essential for their practical application in functional nanodevices. Here we use the field emission (FE) technique to research nanomaterials and establish a generalized Schottky-Nordheim (SN) model, in which an important parameter λ (the image potential factor) is first introduced to describe the effective image potential. By regarding λ as the criterion, their energy-band structure can be identified: (a) λ = 1: metal; (b) 0.5 < λ < 1: n-type semiconductor; (c) 0 < λ < 0.5: p-type semiconductor. Moreover, this method can be utilized to qualitatively evaluate the doping-degree for a given semiconductor. We test numerically and experimentally a group of nanomaterial emitters and all results agree with our theoretical results very well, which suggests that our method based on FE measurements should be an ideal and powerful tool to fast ascertain the conduction-type of nanomaterials.

Electron Emission Devices for Energy‐Efficient Systems

“…Apart from the aforementioned applications, the utilization of VFEDs has extended to X‐ray sources, electric solar wind sail, high‐frequency pulse generator, fast identification of conduction type of nanomaterials, and an electrostatic ion pump…”

Publisher Correction to: Theory of field emission

“…They derive two correction factors to modify the FN theory based on the image potential effect [7,[11][12][13][16][17][18]. Further, the image potential effect was modified by introducing a parameter λ to tune its strength for different semiconductors and rewrite the FN and SN formulas into a compact form, [6,19,20]…”

“…It should be pointed out that we introduce the λ-dependent the correction factors in equations (3) and (4) to describe the image potential effect for different materials of emitters [6]. (1) When λ = 1 the generalized field emission formula in equation (2) is the pure SN formula, which means the emitter being metallic.…”

“…More interestingly, Some generalized formulations beyond the Fowler-Nordheim theory have been proposed for the Luttinger Liquids and the single-wall carbon nanotubes [4,5]. Understanding the behaviors of field emission not only allows us to improve the performance of field emission for these new kinds of nano materials, but also provide a way to detect the physical properties of new nano-materials by field emission [6]. a e-mail: stslsd@mail.sysu.edu.cn…”

“…In fact, when we compare the theoretical prediction and experimental data we face a fatal difficulty [7]. There is no a directly way to compare the theoretical prediction and experimental data for all theoretical formulations of field emission because all theoretical formulations of field emission can be expressed only in terms of the current density versus the local field at the emitter, J(F ), [4][5][6][7][8][9] but the experimental measurements are only the total current versus the voltage between the anode and emitter [1][2][3]6,9,10]. In general, the theoretical total current should be expressed as…”