Thermal stability of a partly Fe-intercalated GaSe film

A single crystal film of layered GaSe epitaxially grown onto a Si(1 1 1) substrate has been partly intercalated at room temperature under ultra-high vacuum. Then it was vacuum annealed sequentially at increasing temperatures up to 850°C and studied at each step by low energy electron diffraction, Auger electron spectroscopy and photoemission yield spectroscopy. It is shown that the Fe-intercalated GaSe is perfectly stable until above 400°C. At higher temperatures, the intercalated Fe is destabilised and is fully trapped into the Si substrate, restoring an Fe free GaSe crystalline film which decomposes above 600°C.