Surface segregation of interstitial manganese in Ga1−xMnxAs studied by hard x-ray photoemission spectroscopy
نویسندگان
چکیده
The effects of low-temperature annealing and oxidation of the dilute magnetic semiconductor Ga1−xMnxAs are studied by photoemission spectroscopy in the hard x-ray regime HAXPES , with special attention to the depth profile of both concentration and chemical state of manganese. Annealing of Ga1−xMnxAs in air at 190 °C for up to 150 h leads to an enrichment of manganese at the surface accompanied by an increase in the native oxide layer. These observations are consistently explained by thermally activated surface segregation of interstitial Mn and its subsequent passivation by oxidation, thereby confirming a recently suggested mechanism for an enhancement of the Curie temperature upon annealing.
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