We here show that inverted-pyramid (IP) textures can be fabricated on single-crystalline Si wafer by simply irradiating the surface with a nanosecond pulsed laser at 532 nm, followed by alkali etching. This process is fundamentally based on the laser-induced melting of material. When exposed to three interfering laser beams, the surface was locally melted in a periodic fashion in accordance with the interference pattern. This generated concave holes on the surface because the melted material overflowed and condensed at the periphery. When subsequently etched by KOH, the internal morphology of the concave holes changed into an IP shape as a result of the position-dependent different etching rates. Uniform IP structures could be obtained with a minimum reflectance of 15.8%.
Bibliographical noteFunding Information:
This work was supported by the New & Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea Government Ministry of Knowledge Economy (Grant 20103020010080 ). The authors thank the members of Prof. D. Kim׳s group, in the Department of Materials Science and Engineering, Korea University, for their help in solar cell fabrication.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering