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Papers by Author: János Mizsei

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Investigation of Additional States in the Silicon Carbide Surface after Diffusion Welding

Authors: János Mizsei, Oleg Korolkov, Natalja Sleptsuk, Jana Toompuu, Toomas Rang

Abstract: This paper is a summary of the experimental study of deep levels in a SiC crystal lattice caused by diffusion welding (DW). Investigations were carried out by DLTS and Kelvin Probe methods. Investigations revealed that DLTS method is not applicable for identification of surface states. Research conducted by the Kelvin Probe method has shown an increase in the density of surface states after the diffusion welding from 2x10¹⁵cm^-2to 3.5x10¹⁶ cm^-2.

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Controlling the Composition of Nanosize Hexagonal WO₃ for Gas Sensing

Authors: Imre Miklós Szilágyi, Sami Saukko, János Mizsei, Péter Király, Gábor Tárkányi, Attila Lajos Tóth, András Szabó, Katalin Varga-Josepovits, János Madarász, György Pokol

Abstract: Hexagonal (h-) WO3 was prepared through heating hexagonal ammonium tungsten bronze (HATB), (NH4)0.07(NH3)0.04(H2O)0.09WO2.95. By adjusting the heating temperature and atmosphere of HATB, we could control the oxidation state of tungsten atoms and the residual NH3/NH4 + content in h-WO3. The as-produced h-WO3 nanoparticles with different composition were tested as gas sensors and the effect of composition on gas sensing properties was studied. Our results showed that oxidized h-WO3 had the best sensitivity to H2S.

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