Field Emission and Cathodoluminescence of ZnS Hexagonal Pyramids of Zinc Blende Structured Single Crystals

Abstract

Single‐crystal hexagonal pyramids of zinc blende ZnS are fabricated by facile thermal evaporation in an ammonia atmosphere at 1150 °C. It is found that ZnS pyramids grow along the [111] crystal axis and possess a sharp tip with a diameter of ∼10 nm and a micrometer‐sized base. The structural model and growth mechanism are proposed based on crystallographic characteristics. This unique ZnS pyramid structure exhibits a low turn‐on field (2.81 V µm−1), a high field‐enhancement factor (over 3000), a large field‐emission current density (20 mA cm−2), and good stability with very small fluctuation (0.9%). These superior field‐emission properties are clearly attributed to the pyramid morphology, with micrometer‐sized bases and nanotips, and high crystallinity. Moreover, a stable UV emission of 337 nm at room temperature is observed and can be ascribed to the band emission of the zinc blende phase. These results suggest that the ZnS hexagonal pyramids can be expected to find promising applications as field emitters and optoelectronic devices.

Zinc sulfide nanowire arrays on silicon wafers for field emitters

“…The average current and the standard deviation were then calculated to be 75.56 and 0.61 μA, respectively, suggesting a high stability of our ZnS nanowire arrays with a deviation as low as ∼0.8%. Such a high field stability is also different from recently reported results [5,3,4,25,26]. We anticipate that the highly stable FE performance shown in this study must be related to their structural characteristics-high single crystalline ZnS nanowire arrays on the Si wafer with sharp cone-shaped nanotips (evidenced in figures 1(e) and (f)), which have a large contact area that can quickly transmit heat from the tip to the wafer, so that the tips can be effectively protected from being destroyed by superheating.…”

The effect of room‐temperature plastic deformation in darkness on the photoluminescence properties of ZnS

“…Figure 3A,B show SEM-CL mapping images taken at a wavelength of 334 nm for specimens deformed up to Ɛ t = 5% and 11%, respectively. Here, the luminescence at 334 nm corresponds to the band-to-band transition of ZnS, which is closely consistent with previous studies, 30 and the wavelength is selected as a probe for imaging so that the glide dislocations are clearly observable. Since the dislocations appear as linear black contrasts in both CL images of Figure 3A,B, the carrier recombination via band-to-band transition is suppressed at dislocations, meaning different recombination processes at dislocations from that in dislocation-free regions.…”

Self-assembled highly symmetrical ZnS nanostructures and their cathodoluminescence

“…For the visible emission, generally it is believed that some catalyst-introduced deep levels or Zn vacancy-related structural defect in the ZnS lattice host may induce such emission. In addition, some structural defects such as point defects, microtwins and dopants (Mn 2 + ) incorporated into the ZnS lattice were also reported [16], and various defect-related emissions in the range of 400-800 nm have been observed in diverse ZnS structures [9,17,18]. In this work, no microtwin or stacking fault was found in ZnS nanostructures during HRTEM observation and ED analysis so the effect of these structural defects on the visible emission can be basically excluded.…”