Growth and electronic and magnetic properties of $α-FeSe$ films on GaAs (001) substrates

FeSe films have been grown on GaAs (001) substrates by low-pressure metal organic vapor deposition at different temperatures. X-ray diffraction analysis indicated that the FeSe films grown at substrate temperatures $(Ts)$ between 220 and $340°C$ were preferentially oriented with tetragonal structure. It was not possible to deposit films at $Ts$ above $400°C$⁠. The atomic molar ratios of $Se∕Fe$ increased with increasing the flow rate of $H2Se∕Fe(CO)5$ and the growth temperature. The electronic property results showed that the conductive type of FeSe could be adjusted by controlling the growth temperature. The coercivity of FeSe decreased with increasing the growth temperature from $220to300°C$ due to the improvement of crystal quality.