Study of thermally activated reaction between Mn and GaAs(111) surface

We investigate the chemical reactivity of ultra-thin films of Mn on As-terminated (111) GaAs surface kept at ultra-high vacuum conditions in the temperature interval ranging from room temperature to 400 °C. The experiments were performed using a customized molecular beam epitaxy system equipped with reflection high energy electron diffraction and X-ray photoelectron spectroscopy techniques. These analyses were complemented with X-ray diffraction measurements to put in evidence the formation of intermediate compounds. Only Ga1 − xMnxAs and sub-arsenised MnAsx compounds are possibly formed below 200 °C. The onset of the reactivity occurs around 200 °C when ordered compounds such as MnAs and MnGa are observed. The formation of compounds more rich in Mn like Mn3Ga and Mn2As is found for deposition temperatures of 300 and 400 °C.