High Current Field Emission from Large-Area Indium Doped ZnO Nanowire Field Emitter Arrays for Flat-Panel X-ray Source Application

Abstract

Large-area zinc oxide (ZnO) nanowire arrays have important applications in flat-panel X-ray sources and detectors. Doping is an effective way to enhance the emission current by changing the nanowire conductivity and the lattice structure. In this paper, large-area indium-doped ZnO nanowire arrays were prepared on indium-tin-oxide-coated glass substrates by the thermal oxidation method. Doping with indium concentrations up to 1 at% was achieved by directly oxidizing the In-Zn alloy thin film. The growth process was subsequently explained using a self-catalytic vapor-liquid-solid growth mechanism. The field emission measurements show that a high emission current of ~20 mA could be obtained from large-area In-doped sample with a 4.8 × 4.8 cm2 area. This high emission current was attributed to the high crystallinity and conductivity change induced by the indium dopants. Furthermore, the application of these In-doped ZnO nanowire arrays in a flat-panel X-ray source was realized and distinct X-ray imaging was demonstrated.

Achieving High Current Stability of Gated Carbon Nanotube Cold Cathode Electron Source Using IGBT Modulation for X-ray Source Application

“…The energy spectrum was recorded under 50 kV anode voltage by the Cd-Te X-ray energy spectrum detector, as shown in Figure 8 . The two peaks at 17.48 and 19.58 keV in the X-ray spectrum correspond to characteristic emissions of the K-shell of the Mo target [ 48 ].…”

Fully Vacuum-Sealed Diode-Structure Addressable ZnO Nanowire Cold Cathode Flat-Panel X-ray Source: Fabrication and Imaging Application

“…Chen et al reported a large-area diode structure flat-panel X-ray source with ZnO nanowire cold cathode and high contrast X-ray images were obtained [35,36]. Flat-panel X-ray sources up to 4 inches in diagonal size have been demonstrated [37,38]. The above-mentioned work demonstrates the feasibility of using ZnO nanowire cold cathode for flat-panel X-ray sources.…”

Recent Progress on ZnO Nanowires Cold Cathode and Its Applications

“…Subsequently, a double-sided irradiating flat-panel X-ray source using ZnO nanowires was also demonstrated by their group [ 110 ], which utilized both the transmission and reflection of X-rays with ~200 mGy/min dose rate. Another flat-panel X-ray source has also been fabricated by using In-doped ZnO nanowires [ 41 ].…”

“…For example, in most of the reported works, only the nanowire morphology [39] and density [35,40] can be modified by adjusting the stress of the initial Zn thin film. Even though a recent work has realized In doping in oxidized ZnO nanowire [41], the control of doping concentration and other high melting point materials doping still remain challenging. [34], with the permission of Elsevier, 2017.…”

“…Subsequently, a double-sided irradiating flat-panel X-ray source using ZnO nanowires was also demonstrated by their group [110], which utilized both the transmission and reflection of X-rays with ~200 mGy/min dose rate. Another flat-panel X-ray source has also been fabricated by using In-doped ZnO nanowires [41]. Since the major advantage of a flat-panel X-ray source is its addressing capability, the ultimate goal for the research of flat-panel X-ray sources is to realize an addressable device.…”