Rough silicon surfaces studied by optical methods

Wang

Journal of Applied Physics

et al. 2009

We demonstrate the fabrication of surface profile-controlled close-packed Si nanorod arrays ͑NRAs͒, using a scalable and integrated circuit compatible process combining colloidal lithography and reactive ion etching. Si NRAs exhibit broadband, omnidirectional, and polarization-insensitive antireflection ͑AR͒ properties and enhance the hydrophobicity. The effect of surface profiles of periodic NRAs on the AR and hydrophobicity was investigated systematically. The Si NRAs function as both self-cleaning and AR layers, which offer a promising approach to enhance the solar cell energy conversion efficiency.

Section: Resultsmentioning

confidence: 99%

Surface profile-controlled close-packed Si nanorod arrays for self-cleaning antireflection coatings

Wang

Journal of Applied Physics

et al. 2009

Phys. Status Solidi (c)

“…with the rms values of the heights equal to several tens or hundreds nanometers) with a wide interval of spatial frequencies [1][2][3][4][5][6]. In this case it is not possible to use simple models of this roughness employed within the known theories of the interaction of light with rough surfaces that have been utilized so far (e.g.…”

Section: Introductionmentioning

confidence: 97%

“…(2) will be presented elsewhere. The reflectance of the rough GaAs surface covered with the triple layer has been expressed as [1,2]:…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic ellipsometry and reflectometry of statistically rough surfaces exhibiting wide intervals of spatial frequencies

Ohlı́dal

Nečas

Franta

2008

Two optical methods for the optical characterization of the statistically rough surfaces exhibiting wide intervals of spatial frequencies are presented. These methods employ the combination of variable angle spectroscopic ellipsometry and near‐normal spectroscopic reflectometry. The first method is based on combining the scalar diffraction theory and effective medium theory while the second method combines the scalar diffraction theory with Rayleigh‐Rice theory.Both the methods are applied to the optical characterization of statistically rough GaAs surfaces prepared by thermal oxidation. It is shown that both the methods can be utilized for characterization of these surfaces in a reasonable way, however, the latter is more suitable for this purpose. The results of the optical characterization of the selected rough GaAs surface are supported by those obtained using atomic force microscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Phys. Status Solidi (c)

“…The slightly rough surface was prepared by anodic oxidation and following dissolution the anodic oxide layer (AOL) formed. The detailed technological procedure of the preparation of rough silicon surfaces is described in paper [13]. Finally, all the surfaces, of both the samples, were covered by the same NOL, because the NOL, originally present on the smooth surfaces [14] and transmittance T for the smooth silicon wafer: TAB -calculated using the optical constants from Refs.…”

Section: Introductionmentioning

confidence: 99%

Optical quantities of rough films calculated by Rayleigh‐Rice theory

Franta

Ohlı́dal

Nečas

2008

Experimental ellipsometric and spectroscopic data of a randomly rough silicon substrate are treated using several theoretical approaches. It is shown that the effective medium approximation and scalar diffraction theory are unsuitable approaches for treating the experimental data of rough surfaces containing spatial frequencies comparable with the wavelength of incident light. Using the Rayleigh‐Rice theory one can obtain an excellent fit of the experimental data and very close agreement between the values of the statistical parameters determined using the optical method and atomic force microscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)