Photoluminescent or blackened silicon surfaces synthesized with copper-assisted chemical etching: For energy applications

Ken Hua Kuo, Wei Hao Ku, Benjamin T.H. Lee

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The metal-assisted chemical etching (MACE) of silicon-based substrates can fabricate nanostructures for various energy applications. The drawback of using copper as a replacement for noble metals in MACE (i.e. Cu-ACE) is the self-dissolution of Cu during processing. However, the implementation of two-step processing, including electroless metal deposition and oxidant (H2O2)–assisted hydrofluoric etching, solves the issue. Here, we determined that when p++-type silicon was applied in the Cu-ACE process, a photoluminescent silicon layer appeared on the etched surface. This result was surprising because photoluminescent silicon is fairly difficult to achieve with regular MACE processing and p++-type silicon is also unsuitable for MACE processing, even when used as an ‘etch-stop’ substrate. On the other hand, when using ultraviolet (UV) irradiation with Cu-ACE, a blackened silicon surface, rather than photoluminescent silicon, developed. Here, we demonstrate a technique for either producing a photoluminescent silicon surface or blackening the silicon surface by single Cu-ACE processing. Cu-ACE processing can be developed into a cost-efficient production technology for silicon-based energy applications, such as silicon photonics and silicon solar cells.

Original languageEnglish
Article number024006
JournalECS Journal of Solid State Science and Technology
Volume9
Issue number2
DOIs
StatePublished - 17 Jan 2020

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