Investigation of porous GaAs layers formed on n+-type GaAs by electrochemical anodization in HF solution

✍ Scribed by Beji, L. ;Sfaxi, L. ;BenOuada, H. ;Maaref, H.

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 333 KB
• Volume: 202
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200406895

✦ Synopsis

Abstract

The electrochemical etching of n^+^‐type GaAs in a hydrofluoric acid (HF) solution results in the formation of a porous layer. The current–potential characteristic I(V) of the n^+^‐type GaAs–HF electrolyte interface shows that pore formation started at a breakdown anodic potential of about 2.5 V independent of the HF concentration. In addition, it is also shown that an electropolishing of the semiconductor started over a critical anodic potential value. The morphology and photoluminescence (PL) of the porous samples were investigated. It has been shown that the porous layer surface morphology consists of arbitrarily shaped crystallites, the pores grow deeply in the substrate and, under some electrochemical conditions, etch pits can be formed. The porous layers exhibited an intense and broad PL band, compared to that of the starting GaAs, composed of elementary bands located below and above the band gap of the starting GaAs. The elementary bands located above the band gap were attributed to GaAs nanocrystals. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)