Enhanced blue responses in nanostructured Si solar cells by shallow doping

Sieun Cheon, Doo Seok Jeong, Jong Keuk Park, Won Mok Kim, Taek Sung Lee, Heon Lee, Inho Kim

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Optimally designed Si nanostructures are very effective for light trapping in crystalline silicon (c-Si) solar cells. However, when the lateral feature size of Si nanostructures is comparable to the junction depth of the emitter, dopant diffusion in the lateral direction leads to excessive doping in the nanostructured emitter whereby poor blue responses arise in the external quantum efficiency (EQE). The primary goal of this study is to find the correlation of emitter junction depth and carrier collection efficiency in nanostructured c-Si solar cells in order to enhance the blue responses. We prepared Si nanostructures of nanocone shape by colloidal lithography, with silica beads of 520 nm in diameter, followed by a reactive ion etching process. c-Si solar cells with a standard cell architecture of an Al back surface field were fabricated varying the emitter junction depth. We varied the emitter junction depth by adjusting the doping level from heavy doping to moderate doping to light doping and achieved greatly enhanced blue responses in EQE from 47%-92% at a wavelength of 400 nm. The junction depth analysis by secondary ion mass-spectroscopy profiling and the scanning electron microscopy measurements provided us with the design guide of the doping level depending on the nanostructure feature size for high efficiency nanostructured c-Si solar cells. Optical simulations showed us that Si nanostructures can serve as an optical resonator to amplify the incident light field, which needs to be considered in the design of nanostructured c-Si solar cells.

Original languageEnglish
Article number125102
JournalJournal of Physics D: Applied Physics
Volume51
Issue number12
DOIs
Publication statusPublished - 2018 Feb 28

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Keywords

  • Auger recombination
  • Blue response
  • crystalline Si solar cell
  • nanostructured Si solar cell

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

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