Tuning the thickness of exfoliated quasi-two-dimensional β-Ga2O3 flakes by plasma etching

Yongbeom Kwon, Geonyeop Lee, Sooyeoun Oh, Ji Hyun Kim, Stephen J. Pearton, Fan Ren

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

We demonstrated the thinning of exfoliated quasi-two-dimensional β-Ga2O3 flakes by using a reactive ion etching technique. Mechanical exfoliation of the bulk β-Ga2O3 by using an adhesive tape was followed by plasma etching to tune its thickness. Since β-Ga2O3 is not a van der Waals material, it is challenging to obtain ultra-thin flakes below a thickness of 100 nm. In this study, an etch rate of approximately 16 nm/min was achieved at a power of 200 W with a flow of 50 sccm of SF6, and under these conditions, thinning of β-Ga2O3 flakes from 300 nm down to ∼60 nm was achieved with smooth morphology. We believe that the reaction between SF6 and Ga2O3 results in oxygen and volatile oxygen fluoride compounds, and non-volatile compounds such as GaFX that can be removed by ion bombardment. The opto-electrical properties were also characterized by fabricating solar-blind photodetectors using the plasma-thinned β-Ga2O3 flakes; these detectors showed fast response and decay with excellent responsivity and selectivity. Our results pave the way for tuning the thickness of two-dimensional materials by using this scalable, industry-compatible dry etching technique.

Original languageEnglish
Article number131901
JournalApplied Physics Letters
Volume110
Issue number13
DOIs
Publication statusPublished - 2017 Mar 27

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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