Science and technology of interfaces

Abstract

The advent of submicrometer technologies, the growth of ultrathin layer films and superlattice structures, and the increasing incorporation of quantum well structures in devices have given new impetus and prominence to the science and technology of interfaces. In homoepitaxy and heteroepitaxy of lattice-matched materials and in the heteroepitaxy of dissimilar materials, the issues of interface morphology, planarity and thermal stability are essential for achieving and controlling the artificially structured device materials. Interface-induced strain effects have led to several new phenomena such as: 100% increase in the elastic moduli (“supermodulus effect”) of thin metallic films (CuNi. AuNi, CuPd), the control of the wavelength of emission in thin semiconductor films (InAlAs-InAs-InAlAs), the enhancement of device performance (“pseudomorphic layer growth”) of a number of devices (lasers, transistors etc.), the observation of new transport phenomena in semiconductor heterostructures (indirect-direct switching in short-period GaAsAlAs superlattices). Some examples are discussed in this paper.