Surfaces of Нigh-Tс Superconductors Studied by Means of the Scanning Tunneling Microscope

Observations of the natural surface of BiSrCaCu₂Oₓ sintered ceramics applying the scanning tunneling microscope are reported. Measurements were performed in air at room temperature. It can be deduced from the surface images, on which the growth steps are visible with heights corresponding to the dimension of the unit cell along the c-axis or its multiples, that the bulk orthorhombic structure extends to the surface. The surface investigated is rather clean, inert and metallic in nature. It can be identified as the Bi-O layer.Zadanie pt. Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

Identification of Residual Impurities in Si-Doped MBE Grown GaAs

The changes of dopant vaporization enthalpy in GaAs:Si grown by molecular beam epitaxy revealed the presence of residual donors related to group VI elements. This has been confirmed by deep level transient spectroscopy studies of AlGaAs:Si layers grown in the same MBE system. It is argued that a commonly observed deep trap labelled E2 is probably related to Te, Se or S. The measurements have been performed on near-ideal Al Schottky barriers grown in situ by MBE