The structural and electrical characterization of europium sulfide thin film prepared with e-beam evaporation

Europium(II) sulfide (EuS) belongs to the europium chalcogenides [1]. It is a ferromagnetic semiconductor with a Curie temperature of 16 K. While the magnetic properties of EuS have been extensively studied, investigations of its electrical properties are limited.

In this study, EuS thin films with varying thicknesses (15, 25, and 50 nm) were deposited onto a Si/SiO2 substrate using e-beam evaporation. Subsequently, two Ag contact electrodes with a 0.2 mm spacing were prepared via thermal evaporation using a shadow mask. To investigate the influence of film thickness and temperature on the electrical properties of EuS thin films, current-voltage (I-V) measurements were performed in a temperature range of 300-433K for a voltage range of -2V to +2V. The I-V characteristics exhibited a temperature-dependent behavior, particularly showing an increase in current with rising temperature in the forward bias region. Furthermore, an improvement in Schottky behavior was observed with increasing EuS film thickness. Additionally, the AC electrical and dielectric properties of the EuS thin film were examined in a frequency range of 4 Hz–8 MHz. Capacitance, conductance, impedance, and the Cole-Cole characteristic of EuS were analyzed in detail with respect to frequency, temperature, and film thicknesses.

References

1- Boncher, W., Dalafu, H., Rosa, N., & Stoll, S. (2015). Europium chalcogenide magnetic semiconductor nanostructures. Coordination Chemistry Reviews, 289, 279-288.