Characterization of random reactive ion etched-textured silicon solar cells

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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Wang

Journal of Applied Physics

et al. 2009

Journal of Applied Physics

“…18 In 2001, Zaidi et al published an extensive study on solar cells textured by reactive ion etching (RIE) in SF 6 and O 2 , paying, however, little attention to the actual dry etching process. 19 During the last decade, only few publications treated Black Silicon formation by RIE in SF 6 and O 2 . While Dussart's work examines Black Silicon etching at cryogenic temperatures, 15 Pezoldt et al describe nanostructure fabrication at temperatures between 20 and 30 C. 20 In addition, Jansen et al studied the occurrence and the possible prevention of Black Silicon using different dry etching techniques.…”

mentioning

confidence: 99%

The structural and optical properties of black silicon by inductively coupled plasma reactive ion etching

Steglich

Käsebier

Zilk

et al. 2014

112

Black Silicon nanostructures are fabricated by Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) in a gas mixture of SF6 and O2 at non-cryogenic temperatures. The structure evolution and the dependency of final structure geometry on the main processing parameters gas composition and working pressure are investigated and explained comprehensively. The optical properties of the produced Black Silicon structures, a distinct antireflection and light trapping effect, are resolved by optical spectroscopy and conclusively illustrated by optical simulations of accurate models of the real nanostructures. By that the structure sidewall roughness is found to be critical for an elevated reflectance of Black Silicon resulting from non-optimized etching processes. By analysis of a multitude of structures fabricated under different conditions, approximate limits for the range of feasible nanostructure geometries are derived. Finally, the technological applicability of Black Silicon fabrication by ICP-RIE is discussed

Progress in Photovoltaics

“…Such "black silicon" called structure leads to complete suppression of the reflection in a broad spectral range, as for example, roughly in the range of~250 to~1000 nm. The textured surfaces created by plasma etching, as for example black silicon structures, have already been reported, for example, by Schnell et al [24], by Zaidi et al [25], by Yoo et al [26,27] and recently by Otto et al [28]. Schnell et al developed a SF 6 /O 2 RIE process for the maskless texturing for the creation of black silicon [24].…”

Section: Introductionmentioning

confidence: 99%

“…Schnell et al developed a SF 6 /O 2 RIE process for the maskless texturing for the creation of black silicon [24]. Zaidi et al used a plasma reactor and created a texture based on RIE in a SF 6 /O 2 plasma chemistry, which results in reflections~1-5% for wavelengths in the range of 300-1000 nm [25]. Yoo et al described that by RIE texturing in a SF 6 /O 2 plasma chemistry using a parallel plate reactor powered by a 13.56 MHz RF generator, a needle-like structure is created, described as "black silicon" and corresponds to a relatively low reflection.…”

Section: Introductionmentioning

confidence: 99%

Relation between light trapping and surface topography of plasma textured crystalline silicon wafers

Souren

Rentsch

Sanden

2013

Currently, in the photovoltaic industry, wet chemical etching technologies are used for saw damage removal and surface texturing. Alternative to wet chemical etching is plasma etching. However, as for example, the linear microwave plasma technique, developed by Roth&Rau, has not been implemented in the photovoltaic industry for etching, because of the very low etch rate (<1m/min) and the high cost of ownership related to the etching process. In this study, different front surface textured crystalline silicon wafers obtained by means of the linear microwave plasma technique and the expanding thermal plasma technique are investigated in terms of weighted reflection by using reflectometry (250-1200nm) to study the optical properties of the textures in detail. In addition, atomic force microscopy is used to measure the surface topography to determine statistical roughness parameters, as presented in this paper. Effective light trapping can be obtained by multiple reflection s as well as by a graded layer, which leads to a diffuse front surface, or a combination of both. A graded layer can be described as a smooth transition with increasing refractive index from air to silicon with typical thickness of (200±50)nm. We have found that the average plane tilt angle correlates to the measured weighted reflection. Moreover, we can determine from the aspect ratio whether the light trapping is effective by multiple reflections. From the roughness exponent, which is a measure for the micro roughness, we can determine whether the light trapping is effective by a graded layer