We explore and demonstrate quantum confinement without walls in metal-clad
InAs quantum wells. We observed intersubband absorption from confined state
s in InAs clad with Al, Sb, Nb, W, Pt, Ag, Au, Ti or In. We found that usin
g this novel method, we can explore the physics and chemistry at the metal-
semiconductor interface; reflection, autoionization, well-width fluctuation
and interface reaction. (C) 2000 Academic Press.