Sarıtaş, Sevda; Merhan Muğlu, Günay; Turgut, Erdal; Kundakçı, Mutlu; Yıldırım, Muhammet; Şenay, Volkan

In this research, Mg-doped hematite (α-Fe2O3) thin films with different Mg-doping concentrations were synthesized on glass substrates using the direct current (DC) and radio frequency (RF) magnetron co-sputtering technique, and the changes of some physical properties due to the concentration of the dopant were investigated. The optical, structural, morphological, and elemental properties of the obtained Mg-doped α-Fe2O3 thin films were determined by X-ray diffraction (XRD) analysis, UV–Vis spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), dispersive X-ray spectroscopy and atomic force microscopy (AFM). XRD analysis revealed that the investigated thin films have a rhombohedral crystal structure. The deposition of films at different DC sputtering voltages caused significant variations in stoichiometry and nanostructure. The thin films' band gap energy values were estimated based on absorption measurements, and results ranged from 2.15 eV to 2.69 eV. Raman peaks were observed between 218 cm−1 and 1305 cm−1. The thin films exhibit uniform surface morphology throughout the substrate according to the SEM images. The low RMS roughness values obtained from AFM images showed that the surfaces of Mg:Fe2O3 thin films are smooth. The Mg-doped α-Fe2O3 thin film doped by 150 W DC voltage exhibited a good gas-sensing response at 300 °C. A remarkably quick response/recovery time was achieved.

AtıfScopus19·WoS13·OpenAlex20

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Efil Kutluoğlu, Esra; Öz Orhan, Elif; Bayram, Özkan; Bilge Ocak, Sema

The purpose of this study is to determine the effects of gamma (γ)-ray irradiation on capacitance and conductance features of Al/Graphene/Al2O3/p-Si structure. Graphene has been grown on copper foil by the Chemical Vapor Deposition (CVD) method and transferred onto Al2O3/p-Si by the wet transfer method. After Al/Graphene/Al2O3/p-Si structure has been exposed to 30 kGy and 60 kGy γ-ray irradiation, capacitance, and conductance measurements have been accomplished at 300 K. Electrical parameters have been compared before and after γ-ray irradiation for 50 kHz and 500 kHz. These results have been confirmed that capacitance and conductance values have increased after γ-ray irradiation and, have decreased when the radiation dose was increased from 30 kGy to 60 kGy. It has been observed that series resistance has decreased after 30 kGy radiation dose and has increased with increasing radiation dose.

AtıfScopus13·WoS12·OpenAlex14

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