Atomic surface structure of MOVPE-prepared GaP(111)B

[Display omitted] •MOVPE preparation of GaP(111)B (phosphorus face).•Combination of STM, XPS, AES and AFM measurements with DFT calculations.•Atomic surface structure of GaP(111)B revealed.•Dangling bonds of partially hydrogen-terminated phosphorus face imaged. Controlling the surface formation of t...

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Published inApplied surface science Vol. 534; p. 147346
Main Authors Kleinschmidt, P., Mutombo, P., Berthold, T., Paszuk, A., Steidl, M., Ecke, G., Nägelein, A., Koppka, C., Supplie, O., Krischok, S., Romanyuk, O., Himmerlich, M., Hannappel, T.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 30.12.2020
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Summary:[Display omitted] •MOVPE preparation of GaP(111)B (phosphorus face).•Combination of STM, XPS, AES and AFM measurements with DFT calculations.•Atomic surface structure of GaP(111)B revealed.•Dangling bonds of partially hydrogen-terminated phosphorus face imaged. Controlling the surface formation of the group-V face of (111)-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(111) virtual substrates, we investigate the atomic structure of the MOVPE (metalorganic vapor phase epitaxy)-prepared GaP(111)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.
ISSN:0169-4332
DOI:10.1016/j.apsusc.2020.147346