Beryllium Substitution-Mediated Covalency Engineering Of Ii-Vi Alloys For Lattice Elastic Rigidity Reinforcement

This work is focused on the "classical" IIB-VI wide-band-gap compound-based device problem, e.g. the elusive "longevity" of [(Zn,Cd)-VI]-based blue lasers. Starting with new data, it follows our first proposals (1994, 1995) of novel Be-chalcogenide potentialities. Its foundation is the identification of a structural signature of the epitaxial layer lattice, i.e., the shear modulus C-s = (C-11 - C-12)/2, together with its improved calculation versus a Harrison covalency parameter deduced from his LCAO model. This work confirms the possibility of achieving an elastic rigidity reinforcement of the lattice in (Zn,Cd)-VI alloys through alloying with Be, paving the way to what we call a "covalency engineering" in the II-VI's. We have discovered the existence of Be-based alloys that are Si lattice-matched, a novel application of silicon which was mentioned in our previous proposals. (C) 1998 Elsevier Science B.V. All rights reserved.