Electrochemical nanostructuring of (111) oriented GaAs crystals: from porous structures to nanowires

Beilstein J Nanotechnol. 2020 Jun 29:11:966-975. doi: 10.3762/bjnano.11.81. eCollection 2020.


A comparative study of the anodization processes occurring at the GaAs(111)A and GaAs(111)B surfaces exposed to electrochemical etching in neutral NaCl and acidic HNO3 aqueous electrolytes is performed in galvanostatic and potentiostatic anodization modes. Anodization in NaCl electrolytes was found to result in the formation of porous structures with porosity controlled either by current under the galvanostatic anodization, or by the potential under the potentiostatic anodization. Possibilities to produce multilayer porous structures are demonstrated. At the same time, one-step anodization in a HNO3 electrolyte is shown to lead to the formation of GaAs triangular shape nanowires with high aspect ratio (400 nm in diameter and 100 µm in length). The new data are compared to those previously obtained through anodizing GaAs(100) wafers in alkaline KOH electrolyte. An IR photodetector based on the GaAs nanowires is demonstrated.

Keywords: anodization; crystallographically oriented pores; gallium arsenide (GaAs); nanowires; neutral electrolyte; photocurrent; porous GaAs.

Grants and funding

Eduard Monaico thanks the Alexander von Humboldt Foundation for support. The authors acknowledge financial support from the Ministry of Education, Culture and Research of Moldova under the Grant #20.80009.5007.20. This work has received partial funding from the bilateral Moldova-Belarus Program under the grant 19.80013.50.07.03A/BL as well as from the European Commission under the Grant #810652 "NanoMedTwin".