Effects of oxygen atmosphere on surface properties of ScO/W(100) system as Schottky emitter at high temperature

Kinetics of surface atoms during phase transition of Sc–O/W(100) system at high temperature studied by Auger electron spectroscopy

“…The procedures of the preparation of the (2 Â 1)-(1 Â 2)-and (1 Â 1)-Sc-O/W(1 0 0) surfaces were the same as those in our previous studies [11][12][13]. A W(1 0 0) surface was cleaned by repeated sputterings using 500 eV Ar + ions of $1 lA and flashing at 1900 K.…”

“…The transition from the (2 Â 1)-(1 Â 2) surface to the (1 Â 1) surface was induced by heating at 1700 K in UHV below $8 Â 10 À8 Pa. The phase transition from the (1 Â 1) surface to the (2 Â 1)-(1 Â 2) surface was induced by exposure to oxygen of $5 Â 10 À7 Pa at 1500 K. Details of AES during the phase transition [12,13] are described elsewhere.…”

“…Previous studies [4][5][6][7][8][9][10][11][12][13] have revealed that the Sc-O/W(1 0 0) surface has two phases with surface atomic arrangements of the (1 Â 1) and (2 Â 1)-(1 Â 2) structures at high temperature. The (2 Â 1)-(1 Â 2)-Sc-O/W(1 0 0) surface is formed by heating at 1500 K in oxygen atmosphere.…”

“…In this regard, the authors have been involved in the surface characterization of the Sc-O/W(1 0 0) system using Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and work function measurement at high temperature [4][5][6][7][8][9][10][11][12][13]. Previous studies [4][5][6][7][8][9][10][11][12][13] have revealed that the Sc-O/W(1 0 0) surface has two phases with surface atomic arrangements of the (1 Â 1) and (2 Â 1)-(1 Â 2) structures at high temperature.…”

Auger spectral shape analysis of Sc‐O/W(100) system during phase transition at high temperature

“…The measurement was performed by keeping the (1 × 1) surface at 1500 K, the operating temperature of the Sc-O/W(100) emitter, in the oxygen atmosphere. Since the speed of the transition from the (1 × 1) to (2 × 1)-(1 × 2) surfaces strongly depends on the oxygen partial pressure, [12] i.e. the higher the partial pressure is, the faster the transition is, the oxygen partial pressure was set at ∼5 × 10 −7 Pa, which was low enough to measure the Sc-LMM and O-KLL spectra during the transition.…”