Enhanced Field Emission Properties of Two-Dimensional ZnO Nanosheets Under UV illumination

Abstract

In this paper, ZnO nanosheets were grown on glass substrates by using an aqueous solution at room temperature. It was found that the ZnO nanosheets were structurally uniform and well oriented with the wurtzite structure. The field emission performance of ZnO nanosheets can be greatly enhanced by illuminating UV light. It was found that the turn-on electric field can be reduced from 5.9 to 5.0 V/μm and field enhancement factors (β) can be increased from 1966 to 4202. It is attributed to generate a large number of electrons by UV illumination.Index Terms-Room temperature, ZnO, nanosheet, aqueous solution method, field emitters.

Review—Growth of Al-, Ga-, and In-Doped ZnO Nanostructures via a Low-Temperature Process and Their Application to Field Emission Devices and Ultraviolet Photosensors

“…The FE characteristic was analyzed according to FN theory. 42 Fig. 4a shows the FE current density as a function of the applied electric field in the dark and under UV illumination.…”

“…FE cathodes from ZnO nanostructures have gained significant interest because of their valuable properties, including their high aspect ratio, low work function, general stability, and high electrical conductivity. [41][42][43][44][45][46][47] Compared with other materials, such as GaN, ZnO exhibits better characteristic and potential to fabricate UV photosensors. Highperformance solid-state UV photosensors have attracted interest in recent years.…”

“…Second, a large number of excited electrons are stored at the tips of NWs, thereby causing a subsequent point discharge that reduces the electric field. [41][42][43][44][45][46][47] This article provides a helpful review on doping ZnO 1D and 2D nanostructures. First, the synthesis methods for and the properties of doped ZnO 1D and 2D nanostructures are introduced and discussed.…”

“…A brief future outlook on doped ZnO nanostructures FE devices and UV photosensors is included at the end of the article. [41][42][43][44][45][46][47]…”

Improvement of the UV-Sensing Performance of Ga-Doped ZnO Nanostructures via a Wet Chemical Solution at Room Temperature

“…The ZPD and ZPD-G samples were connected to each other in the form of net-shaped NSs with average thicknesses of 14.2 and 14.4 nm, respectively, and average lengths of 1.45 and 1.48 μm, respectively. The synthesis of nano-flowerlike ZnO structures from an aqueous solution containing Zn(OH) 4 2was recently reported by Huang et al 23 The growth of the nanostructures proceeded via the following chemical reactions: 24 Zn 2OH Zn OH 1 2− is likely the growth unit directly incorporated into the ZnO crystallites under the given conditions. Although the growth of ZnO crystals is mainly determined by the intrinsic structure in a liquid medium, it can also be affected by the external conditions (e.g., solution pH, Zn(OH) 4 2− concentration).…”