Department of Semiconductor Materials Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
Agata K. Tołłoczko
Department of Semiconductor Materials Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
Dominika Majchrzak
Łukasiewicz Research Network—PORT Polish Center for Technology Development, Stabłowicka 147, 54-066 Wrocław, Poland
Detlef Hommel
Łukasiewicz Research Network—PORT Polish Center for Technology Development, Stabłowicka 147, 54-066 Wrocław, Poland
Robert Kudrawiec
Department of Semiconductor Materials Engineering, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
Here we present new findings of a comprehensive study of the fundamental physicochemical properties for GeS and GeSe in bulk form. UV and X-ray photoelectron spectroscopies (UPS/XPS) were employed for the experiments, which were carried out on in situ cleaned (100) surfaces free from contamination. This allowed to obtain reliable results, also unchanged by effects related to charging of the samples. The work functions, electron affinities and ionization energies as well as core level lines were found. The band gaps of the investigated materials were determined by photoreflectance and optical absorption methods. As a result, band energy diagrams relative to the vacuum level for GeS and GeSe were constructed. The diagrams provide information about the valence and conduction band offsets, crucial for the design of various electronic devices and semiconducting heterostructures.
