The effect of sequential deposition of Cu onto a 300 Å-thick film of
layered InSe epitaxially grown onto a Si(111) substrate, has been studied by Auger
electron spectroscopy (AES), low energy electron diffraction (LEED) and photoemission
yield spectroscopy (PYS). Cu coverages were from a few hundredth of a monolayer (in
terms of InSe atomic surface plane: 1 ML = 7.2 × 1014 at/cm2, that is
0.85 Å of Cu-metal) to 300 ML. The effect of annealings up to 370 °C was
also studied. It is shown that Cu has first a non uniform bulk interaction with InSe
which looks like an insertion which saturates at 1 ML of Cu per In2Se2 single
layer. Then it forms islands which fully mask the surface beyond about 150 ML coverage
(130 Å of Cu-metal). Upon annealings beyond 300 °C, the Si substrate behaves
as a Cu sink.