TY - JOUR

T1 - Lift-off of porous germanium layers

AU - Rojas, E. Garralaga

AU - Hensen, J.

AU - Carstensen, J.

AU - Föll, H.

AU - Brendel, R.

N1 - Funding Information: The authors would like to thank Daniel Tutuc and Prof. Rolf Haug from the University of Hannover for the AFM measurements, V. Wiedemeier and G. Berth from the University Paderborn for the µ-Raman measurements, and Bianca Gehring from the ISFH for the technical assistance. The financial support of this work by the Ger- man Ministry for Economy and Technology under contract No. 50JR0641 is gratefully acknowledged. E. Garralaga Rojas specially thanks the European Space Agency for the financial support of his work in the framework of the Networking Partnering Initiative (Co. No. 20250/06/NL/GLC).

PY - 2011/4/22

Y1 - 2011/4/22

N2 - We demonstrate reproducible formation of mesoporous germanium layers suitable for solar energy applications by electrochemical etching in highly concentrated electrolytes. For long anodization times or thick layer formation a porosity gradient is observed leading eventually to high porosity regions and cavity formation at the bottom of the porous layer. A 30 min annealing step at a temperature of 575C in hydrogen atmosphere allows for reorganization and subsequent lift-off. The mean surface roughness increases from 0.31 nm for unprocessed Ge up to 7.85 nm for reorganized Ge as measured by atomic force microscopy. -Raman confocal spectroscopy analysis confirms that etching and annealing do not affect the crystalline structure.

AB - We demonstrate reproducible formation of mesoporous germanium layers suitable for solar energy applications by electrochemical etching in highly concentrated electrolytes. For long anodization times or thick layer formation a porosity gradient is observed leading eventually to high porosity regions and cavity formation at the bottom of the porous layer. A 30 min annealing step at a temperature of 575C in hydrogen atmosphere allows for reorganization and subsequent lift-off. The mean surface roughness increases from 0.31 nm for unprocessed Ge up to 7.85 nm for reorganized Ge as measured by atomic force microscopy. -Raman confocal spectroscopy analysis confirms that etching and annealing do not affect the crystalline structure.

UR - http://www.scopus.com/inward/record.url?scp=79955527619&partnerID=8YFLogxK

U2 - 10.1149/1.3583645

DO - 10.1149/1.3583645

M3 - Article

AN - SCOPUS:79955527619

VL - 158

SP - D408-D411

JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

IS - 6

ER -