Characterization of Bi2Se3:Fe epitaxial films grown by pulsed laser deposition

• Bi2Se3 doped with Fe epitaxial films were grown by pulsed laser deposition.
• Fe–Se bonding possesses Fe in valence state of + 3.
• The Mössbauer spectroscopy showed paramagnetic behavior of the samples.

Iron doped bismuth selenide (Bi2Se3:Fe, 5–8 at.%) films were deposited on Si (100) substrates using pulsed laser deposition at different substrate temperatures. The epitaxial films with high c-axis orientation were grown at 400 °C and 450 °C. X-ray photoelectron spectroscopy revealed the presence of oxidized surface layer and Fe–Se bonding with the Fe valence state of + 3. The valence state was proved by Conversion Electron Mössbauer Spectroscopy. These results, along with quantitative element analysis confirmed the substitution of Bi by Fe ions. The Mössbauer spectroscopy showed paramagnetic behavior of the sample grown at 450 °C, whereas the magnetization measurement revealed weak ferromagnetic signal (~ 103 A/m), attributed with the oxidized layer. The growth at elevated temperatures resulted in a heavy oxidation of the samples.