Sn-doped In2O3 nanowires: enhancement of electrical field emission by a selective area growth

Abstract

Selective area growth of single crystalline Sn-doped In2O3 (ITO) nanowires synthesized via vapor–liquid–solid (VLS) method at 600°C was applied to improve the field emission behavior owing to the reduction of screen effect. The enhanced field emission performance reveals the reduction of turn-on fields from 9.3 to 6.6 V μm−1 with increase of field enhancement factors (β) from 1,621 to 1,857 after the selective area growth at 3 h. Moreover, we find that the screen effect also highly depends on the length of nanowires on the field emission performance. Consequently, the turn-on fields increase from 6.6 to 13.6 V μm−1 with decreasing β values from 1,857 to 699 after the 10-h growth. The detailed screen effect in terms of electrical potential and NW density are investigated in details. The findings provide an effective way of improving the field emission properties for nanodevice application.

The Rational Design of a Single‐Component Photocatalyst for Gas‐Phase CO2 Reduction Using Both UV and Visible Light

“…This is a result of the change in O interaction with an In centre that is more reduced in character because it is surrounded by less than six O atoms (due to the oxygen vacancies). The peak at 532.5 eV has been attributed to surface OH groups42 and agrees well with the O1s spectra for the pure In(OH) 3 peak. From these plots in Figure 4c–e, it is clear that the shoulder peak – with contributions from both vacancies and surface hydroxides – decreases with increasing calcination temperature.…”

“…Indeed, the O1s peak for the In 2 O 3‐x (OH) y samples can be de‐convoluted into three distinct peaks: the main oxide peak at 530.3 eV and two additional peaks at 531.7 eV and 532.5 eV (Figure 4c–e). The peak at 531.7 eV is commonly attributed to the presence of oxygen vacancies in the structure 42, 43. It is also consistent with the observed n‐type position of the Fermi‐levels relative to the conduction bands (Figure 2c), which is typically a result of non‐stoichiometry 44.…”

Carrier dynamics and the role of surface defects: Designing a photocatalyst for gas-phase CO 2 reduction

“…The main portion of the peak is centered around 530 eV and is associated with indium oxide. The shoulder peak at higher binding energies, which decreases with decreasing calcination temperature, is commonly attributed to a combination of defects with contribution from both oxygen vacancies, with a peak centered around 531 eV, and hydroxides, with a peak centered around 532 eV (35,41). The light-gray curves in Fig.…”

Broad compositional tunability of indium tin oxide nanowires grown by the vapor-liquid-solid mechanism

“…In addition ITO NWs have been grown by pulsed laser deposition (PLD) of In 2 O 3 and SnO 2 as shown recently by Meng et al 12 Furthermore, ITO NWs have been obtained from the reaction of In and Sn with O 2 by reactive vapor transport as both metals have low melting points of 157 • C and 232 • C, respectively, and similar vapor pressures. For instance, Chiu et al 13 obtained ITO NWs at 900 • C under a flow of Ar by using 20 nm diameter Au nanoparticles (NPs) on Si(001) and a fixed In:Sn source weight ratio of 9:1 while Chang et al 14 used a fixed In:Sn source weight ratio of 9:1 and obtained ITO NWs on 5 nm Au/Si(001) at 600 • C using Ar,H 2 and O 2 . However, despite all of these efforts only few have investigated in detail the incorporation of Sn and the changes that occur in the crystal structure of ITO NWs by changing the In:Sn source ratio over a broad range.…”