Wet-chemical bromination of Ge (100): A facile surface passivation tool

Graniel Harne A. Abrenica, Mikhail V. Lebedev, Gilbert Okorn, Dennis H. Van Dorp*, Mathias Fingerle

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We demonstrate that wet-chemical surface bromination is an effective and a simple etching method for Ge surface oxide removal, providing excellent reoxidation resistance. Oxide removal and halide passivation for n-type Ge (100) were investigated using time-resolved photoluminescence and X-ray photoemission spectroscopy (XPS). In contrast to HCl, HBr treated Ge surfaces show a strong decrease in minority carrier lifetime, pointing to a surface state spectrum modification. The results from XPS using in situ sample preparation confirm that HBr effectively removes GeO2 and suboxides, providing an air stable surface. Isopropyl alcohol rinsing after Br passivation maintains the chemical surface composition and the electronic structure. In contrast, during H2O treatment in an Ar atmosphere, the brominated Ge surface is unstable, evidenced by emerging Ge-OH groups. The distinct observed upward shift of the surface Fermi level indicates an e- donating behavior of H2O.

Original languageEnglish
Article number062104
JournalApplied Physics Letters
Issue number6
Publication statusPublished - 6 Aug 2018

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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