Effekt of adsorbed Ge atoms on the photoemission properties of GaAs

Abstract

A3B5 semiconductor compounds in the future are the most promising for further detailed consideration. In this regard, gallium arsenide is a semiconductor compound formed by elements of groups III and V of the periodic system – gallium Ga and arsenic As. Gallium arsenide and its surface properties attract much attention of researchers due to the possibility of its wide application in micro- and nanoelectronics technology. Despite numerous studies of the surface of semiconductors, many issues related to its properties and processes at the interface between two phases remain insufficiently clarified, especially in terms of the effect of the surface state on the energy spectrum of electrons in crystals. Interest in these issues is constantly growing not only from a scientific point of view, but also from a practical one, in connection with the development of semiconductor micro- and nanotechnologies. The development of its sections such as thin-layer nanoelectronics and optoelectronics, devices with MIS structures and charge coupling, cold cathodes and efficient photocathodes require an understanding of the processes in the near-surface layer of a semiconductor both with a free surface and with this free surface during the adsorption of other substances on it. This is also important for elucidating the possibility of changing the surface and near-surface properties of solids in a quite definite way. Gallium arsenide is the closest binary analog of germanium. By introducing appropriate impurities, gallium arsenide can be obtained with both n-type and p-type conductivity with different current carrier concentrations. This structure belongs to the crystallographic class of the cubic system, like germanium. Gallium arsenide and germanium crystallize in the structure of zinc blende. In view of the foregoing, it is interesting to study the influence of adsorbed germanium layers on the surface properties of gallium arsenide single crystals of various types of conductivity by photoemission method in ultrahigh vacuum. The questions of the influence of these coatings not only on the emission properties of gallium arsenide single crystals, but also the influence of these adsorbed germanium atoms on the energy structure in the near-surface region of single crystals are considered.