| Abstract: | This study is embedded in the broader context of reactive metal overlayers and passivation on GaAs. High resolution synchrotron-radiation photoemission experiments for Ti coverages on Se-reacted GaAs (110) surfaces show that, contrary to clean Ti-reacted GaAs (110) interface, there is no initial disruption (submonolayer reaction) of the surface involving both Ga and As atoms during early stage of interface formation. However, a delayed Ti involved reaction appears at a trigger coverage of about 1 ML involving only As atoms from the prereacted As Se interface configuration continued by Stranski-Krastanov growth mode. A second reacted phase starts to form two Ga Ti involved configurations replacing Ga Se bonds near a Ti coverage of 4 ML. The preferential chemical trapping of Ti by Se atoms is associated with a smaller interface thickness very likely <10 ML instead of 50 ML in the case of clean Ti/GaAs (110) interface caused by mobile As atoms. |
