Atomic surface structure of MOVPE-prepared GaP(1 1 1)B
| Autor: | Oleksandr Romanyuk, Oliver Supplie, Thomas Hannappel, Gernot Ecke, Pingo Mutombo, Christian Koppka, Peter Kleinschmidt, Andreas Nägelein, Stefan Krischok, Matthias Steidl, Agnieszka Paszuk, Theresa Berthold, Marcel Himmerlich |
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| Rok vydání: | 2020 |
| Předmět: |
Auger electron spectroscopy
Materials science Annealing (metallurgy) Photoemission spectroscopy Dangling bond Analytical chemistry General Physics and Astronomy 02 engineering and technology Surfaces and Interfaces General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Epitaxy 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films law.invention X-ray photoelectron spectroscopy law Metalorganic vapour phase epitaxy Scanning tunneling microscope 0210 nano-technology |
| Zdroj: | Applied Surface Science. 534:147346 |
| ISSN: | 0169-4332 |
| Popis: | Controlling the surface formation of the group-V face of (1 1 1)-oriented III-V semiconductors is crucial for subsequent successful growth of III-V nanowires for electronic and optoelectronic applications. With a view to preparing GaP/Si(1 1 1) virtual substrates, we investigate the atomic structure of the MOVPE (metalorganic vapor phase epitaxy)-prepared GaP(1 1 1)B surface (phosphorus face). We find that upon high-temperature annealing in the H2-based MOVPE process ambience, the surface is phosphorus-depleted, as evidenced by X-ray photoemission spectroscopy (XPS). However, a combination of density functional theory calculations and scanning tunneling microscopy (STM) suggests the formation of a partially H-terminated phosphorus surface, where the STM contrast is due to electrons tunneling from non-terminated dangling bonds of the phosphorus face. Atomic force microscopy (AFM) reveals that a high proportion of the surface is covered by islands, which are confirmed as Ga-rich by Auger electron spectroscopy (AES). We conclude that the STM images of the samples after high-temperature annealing only reflect the flat regions of the partially H-terminated phosphorus face, whereas an increasing coverage with Ga-rich islands, as detected by AFM and AES, forms upon annealing and underlies the higher proportion of Ga in the XPS measurements. |
| Databáze: | OpenAIRE |
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