Effect of Cu on InSe/Si(111) heterojunctions

¹ Laboratoire Surfaces des Matériaux, Institut de Physique, Université d'Oran Es-Sénia, 31100 Oran, Algeria
² Laboratoire de Minéralogie Cristallographie (UMR 7590 du CNRS), Université Pierre et Marie Curie, case 115, 4 place Jussieu, 75252 Paris Cedex 05, France

Corresponding author: sebenne@lmcp.jussieu.fr

Received: 19 April 1999
Revised: 22 July 1999
Accepted: 7 September 1999
Published online: 15 September 1999

Abstract

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.