Metal-assisted chemical etching of Ge surface and its effect on photovoltaic devices

Seunghyo Lee, Hyeokseong Choo, Changheon Kim, Eunseok Oh, Dongwan Seo, Sangwoo Lim

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16 Citations (Scopus)


Ge surfaces were etched by means of metal-assisted chemical etching (MaCE). The behavior of the MaCE reaction in diluted H 2 O 2 was compared with that of a conventional etchant of HF/H 2 O 2 /H 2 O mixture (FPM). Herein we first report that a pyramidal structure on Ge (0 0 1) can be prepared by MaCE in dilute H 2 O 2 solution, without the use of HF. Contrastingly, an octagonal trench structure was prepared by 4/5/1 FPM treatment of Ge (0 0 1) surface. This octagonal structure consisted of a square base, four large facets connected to the base, and other four small facets adjacent to the four large facets, which were considered to be (0 0 1), {1 1 0}, and {1 1 1}, respectively. The octagonal trench was formed as a result of the difference in etch rate of Ge depending on the orientation: {1 0 0} > {1 1 0} > {1 1 1}. Ge surfaces treated by MaCE exhibited improved solar cell efficiency due to their improved light absorption, which led to significant increases in the cells' short circuit current and fill factor. The results suggest that optimized MaCE procedures can be an effective method to improve the performance of Ge-based photovoltaic devices.

Original languageEnglish
Pages (from-to)129-138
Number of pages10
JournalApplied Surface Science
Publication statusPublished - 2016 May 15

Bibliographical note

Funding Information:
This work was supported by the Priority Research Centers Program ( 2009-0093823 ) through the National Research Foundation of Korea (NRF), funded by the Ministry of Education . This work was also supported by the New & Renewable Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), funded by the Korean Government Ministry of Trade , Industry & Energy (No. 20143020010860 ). This work was also supported by the Industrial Strategic Technology Development Program ( 10049099 , Development of Total Front-End Cleaning Technologies for Ge and III-V Semiconductor Channel), funded by the Korean Ministry of Trade, Industry & Energy .

Publisher Copyright:
© 2016 Elsevier B.V. All rights reserved.

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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