Size control and vacuum-ultraviolet fluorescence of nanosized KMgF3 single crystals prepared using femtosecond laser pulses

We fabricated nanosized KMgF3 single crystals via a dry pulsed laser ablation process using femtosecond laser pulses. The sizes, shapes, and crystallographic properties of the crystals were evaluated by transmission electron microscopy (TEM). Almost all of the particles were spherical with diameters of less than 100 nm, and they were not highly agglomerated. Selected-area electron diffraction and high-resolution TEM analyses showed that the particles were single crystals. Particle diameter was controlled within a wide range by adjusting the Ar ambient gas pressure. Under low gas pressures (1 and 10 Pa), relatively small particles (primarily 10 nm or less) were observed with a high number density. With increasing pressure, the mean diameter increased and the number density drastically decreased. Vacuum-ultraviolet cathodoluminescence was observed at 140–230 nm with blue shift and broadening of spectrum

Vacuum ultraviolet field emission lamp utilizing KMgF3 thin film phosphor

We demonstrated a field emission lamp by employing a KMgF3 thin film as a solid-state vacuum ultraviolet phosphor. The output power of the lamp was 2 μW at an extraction voltage of 800 V and acceleration voltage of 1800 V, and it operated at wavelengths 140-220 nm, which is the shortest wavelength reported for solid-state phosphor lamps. The thin film was grown on MgF 2 substrate by pulsed laser deposition. Its conversion efficiency was almost equivalent to a single KMgF3 crystal, and it had emission peaks of 155 and 180 nm in wavelength. These peaks are attributed to transitions from the valence anion band to the outermost core cation band and correspond well with emission peaks previously reported from the crystal. Additionally, we obtained a thermal-free and low-power consumption lamp by employing carbon nanofibres (CNFs) as a field emitter. A CNF emitter was easily grown at room temperature and can be grown on flexible materials

Vacuum Ultraviolet Field Emission Lamp Consisting of Neodymium Ion Doped Lutetium Fluoride Thin Film as Phosphor

A vacuum ultraviolet (VUV) field emission lamp was developed by using a neodymium ion doped lutetium fluoride (Nd3+ : LuF3) thin film as solid-state phosphor and carbon nanofiber field electron emitters. The thin film was synthesized by pulsed laser deposition and incorporated into the lamp. The cathodoluminescence spectra of the lamp showed multiple emission peaks at 180, 225, and 255 nm. These emission spectra were in good agreement with the spectra reported for the Nd3+ : LuF3 crystal. Moreover, application of an acceleration voltage effectively increased the emission intensity. These results contribute to the performance enhancement of the lamp operating in the VUV region