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Current issue   Ukr. J. Phys. 2017, Vol. 62, N 8,p.692-698


Mel’nyk P.V., Nakhodkin M.G., Fedorchenko M.I.

Taras Shevchenko National University of Kyiv
(64/13, Volodymyrs’ka Str., Kyiv 01601, Ukraine)

Influence of Changes in Defect States on the Properties of Si–Gd–O Photocathode

Section: Solid Matter
Original Author's Text:  Ukrainian/English

Abstract: Changes in the electronic and emission properties of a photocathode on the basis of a multi-layered structure of oxidized Gd atoms (probably, Gd2O3) on the Si(100) substrate after the
deposition of additional layers of Gd atoms onto its surface and the bombardment with Ar
ions have been studied by the methods of photoelectron ( hv= 2.3÷10.2 eV) and Auger electron spectroscopies. The modifcations of photocathode properties are found to depend on the
defectness of the near-surface photocathode layer, being a result of the change in the concentration of localized electron states located in the energy gap of Gd2O3. It is shown that the
bombardment of a Si–Gd–O cathode with Ar ions and its exposition to atomic hydrogen can be
used to control its spectral and emission characteristics. A possibility to use the energy diagram
proposed by us for the photocathode to qualitatively analyze its properties is confrmed.

Key words: Si, Gd, O, Gd2O3, structural defects, electronic and emission properties.