Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 72: Poster Session: Si-based Photovoltaics / Inorganic Photovoltaics / Structure and Transport in Organic Photovoltaics / Organic Semiconductors
HL 72.1: Poster
Wednesday, March 28, 2012, 16:00–19:00, Poster D
Porous silicon antireflective layer fabricated by platinum nanoparticle assisted chemical etching — •Xiaopeng Li1, Stefan Schweizer2, and Ralf Wehrspohn3 — 1Max-Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany — 2Martin-Luther-Universität Halle-Wittenberg, Germany — 3Fraunhofer Institute for Mechanics of Materials at Halle, Germany
Meal assisted chemical etching (MaCE), is a purely solution processed, high throughput technique. Si wafers loaded with metal nanoparitcles (NPs) such as Ag, Au or Pt, are immersed in solution containing HF and an oxidant. Etching preferentially occurs beneath the metal NPs, enabling the formation of nanopores and nanowires. Here, we presented for the first time, the formation of uniform porous silicon layer with pore size ranging from meso- to macro-size, by using platinum nanoparticle assisted chemical etching (PaCE). Various factors influencing the porous silicon morphology including PtNP density, silicon doping level, and H2O2 concentration were systematically studied. A new etching mechanism was evaluated. The formed macroporous Si showed the reflectance below 2.5% at the wavelength range of 300 nm to 1000 nm, and mesoporous Si exhibited broadband light absorption, even in the near infrared range. With perfect light trapping, macroporous silicon demonstrated more than 10 mA/cm2 photocurrent increase than that of controlled planar Si samples.