Scanning tunneling microscopy study of GaAs 001/surfaces

While GaAs 001.is the most commonly used substrate in fabrication of wireless and opto-electronic devices based on III–V compound semiconductors by molecular beam epitaxy MBE., metallorganic chemical vapor deposition MOCVD. and related techniques, its surface structure have been disputed since the beginning of development of the techniques. Invention of scanning tunneling microscopy STM.has revolutionized the approach of surfacerinterface investigation, contributing greatly in the atomistic understanding of the GaAs surface phases. This paper reviews the STM studies of principal reconstructions, from As-rich c 4=4., 2=4, 2=6 to Ga-rich 4=2 and 4=6, found on the GaAs 001.surface. These studies, together with advanced theoretical efforts, have helped us to establish a unified structural model for various reconstructions, with which we can now explain most of the observations and long-standing controversies in atomic structures and surface stoichiometries. q1999 Elsevier Science B.V. All rights reserved.