Surface properties of Sc–O/W() system as emitter at room and high temperatures

Self-recovery function of Sc–O/W() system as Schottky emitter

“…The results strongly suggested that the superior characteristics of the Sc-O/W(1 0 0) system used as an emitter are due to the decrease of the work function caused by the formation of Sc-O electric dipoles aligning into the p(2 · 1)-p(1 · 2) double domain structure [9][10][11]. It was also confirmed that the surface properties, i.e., the atomic arrangement, composition and chemical bonding state of the Sc-O/W(1 0 0) surface, are very stable at the operating temperature of the Sc-O/W(1 0 0) emitter.…”

“…Regarding the Sc-O/W(1 0 0) Schottky emitter, the authors have carried out the surface characterization of the Sc-O/W(1 0 0) system at the operating temperature of the emitter using Auger electron spectroscopy (AES), ion scattering spectroscopy (ISS), low-energy electron diffraction (LEED) and work function measurement [8][9][10][11]. The results strongly suggested that the superior characteristics of the Sc-O/W(1 0 0) system used as an emitter are due to the decrease of the work function caused by the formation of Sc-O electric dipoles aligning into the p(2 · 1)-p(1 · 2) double domain structure [9][10][11].…”

Self‐recovery function of p(1×1)‐Sc‐O/W(100) system used as Schottky emitter

“…The surface structure is still close to the p 2 ð 1 -p 1 ð 2 structure. In contrast to the change in the surface composition and atomic arrangement upon heating at ¾1600 K, it has been confirmed already that the properties of the Sc-O/W(100) surface prepared at ¾1500 K (step (iv)) are very stable against further heating at ¾1500 K. 10,12 These results revealed that the surface properties of the Sc-O/W(100) system are significantly different between those prepared by heating at ¾1500 and at ¾1600 K. Note that the heating treatment at ¾1600 K following step (v) revealed that the p-p intensities of the AES spectra and the LEED pattern show no significant changes with further heating at ¾1600 K for ¾60 min.…”

“…In previous studies, the decrease of the work function by ¾1.4 eV with respect to that of the clean W(100) surface after the heating treatment was confirmed by work function measurement using the AES-ISS- measurement apparatus. 8,10 By comparing the p-p intensities of the AES peaks shown in Fig. 1 with those obtained using the AES-ISS- measurement apparatus, 8,10 the p-p intensity from the Sc-O/W(100) surface (the work function of which is decreased) is close to those at step v 0 in Fig.…”

“…8,10 This surface is very stable and exhibits a self-recovery function at the operating temperature of the Sc-O/W(100) emitter, resulting in a high stability of electron emission. High reproducibility of the superior electron emission of the Sc-O/W(100) emitter could be obtained with a pretreatment of heating at ¾1700 K and then operating at ¾1500 K. Taking into account that the shape of the sample used in the present study is different from that of the emitter, and that the high voltage is applied at the tip of the emitter during operation, verification of the present proposal using a real emitter is necessary.…”