Sub-Wavelength Texturing for Solar Cells Using Interferometric Lithography

2006 ◽  
Vol 51 ◽  
pp. 115-120 ◽  
Author(s):  
W.L. Chiu ◽  
M.M. Alkaisi ◽  
G. Kumaravelu ◽  
R.J. Blaikie ◽  
R.J. Reeves ◽  
...  
Keyword(s):  
Defect Density ◽  
Substantial Reduction ◽  
Surface Texturing ◽  
Silicon Substrates ◽  
Textured Surface ◽  
Large Area ◽  
Periodic Patterns ◽  
Interferometric Lithography ◽  
Plasma Reflection ◽  
Sub Wavelength

We have employed Interferometric Lithography (IL) for sub-wavelength surface texturing on large area silicon substrates. Low defect density Reactive Ion Etching (RIE) processes have been developed to transfer the pattern into the silicon using SF 6 plasma. Reflection measurements on the sub-wavelength textured surface have been carried out and show a substantial reduction from ~30% to below 4% over the spectrum range from 400nm to 1200nm. IL is a mask-less lithography technique which is used to define periodic patterns. The theoretical limit of the pitch size of the structure is half of the wavelength of the light source. Hence, the sub-wavelength patterns can be achieved easily. Moreover, sub-wavelength texturing requires short RIE processes; most of the plasma-induced damage on the silicon surface can be avoided.

scholarly journals Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

Friction ◽  
2021 ◽  
Author(s):  
Chia-Jui Hsu ◽  
Andreas Stratmann ◽  
Simon Medina ◽  
Georg Jacobs ◽  
Frank Mücklich ◽  
...  
Keyword(s):  
Boundary Lubrication ◽  
Surface Texturing ◽  
Contact Stresses ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Wear Loss ◽  
Textured Surface ◽  
Periodic Patterns ◽  
Rolling Bearings ◽  
Fatigue Lifetime

AbstractLaser surface texturing (LST) has been proven to improve the tribological performance of machine elements. The micro-scale patterns manufactured by LST may act as lubricant reservoirs, thus supplying oil when encountering insufficient lubrication. However, not many studies have investigated the use of LST in the boundary lubrication regime, likely due to concerns of higher contact stresses that can occur with the increasing surface roughness. This study aims to examine the influence of LST on the fatigue lifetime of thrust rolling bearings under boundary lubrication. A series of periodic patterns were produced on the thrust rolling bearings, using two geometrically different designs, namely cross and dimple patterns. Base oil ISO VG 100 mixed with 0.05 wt% P of zinc dialkyldithiophosphate (ZDDP) was supplied. The bearings with cross patterns reduce the wear loss by two orders of magnitude. The patterns not only retain lubricant in the textured pockets but also enhance the formation of an anti-wear tribofilm. The tribofilm generation may be improved by the higher contact stresses that occur when using the textured surface. Therefore, in contrast to the negative concerns, the ball bearings with cross patterns were instead found to increase the fatigue life by a factor of three.

LARGE AREA NANOSCALE PATTERNING BY INTERFEROMETRIC LITHOGRAPHY – NANOPHOTONICS AND NANOFLUIDICS

2008 ◽  
Vol 18 (04) ◽  
pp. 889-899 ◽  
Author(s):  
S. R. J. BRUECK
Keyword(s):  
Silica Nanoparticles ◽  
Large Scale ◽  
Frequency Doubling ◽  
Silicon Substrates ◽  
Large Area ◽  
Scientific Investigations ◽  
Nanoscale Patterning ◽  
Colloidal Deposition ◽  
Interferometric Lithography ◽  
Porous Walls

Interferometric lithography offers a facile, inexpensive, large-area fabrication capability for the formation of large areas of nanoscale periodic features. A self-aligned frequency doubling process to a 22-nm half-pitch is demonstrated. Many investigations of nanoscale phenomena require large-area samples, both for scientific investigations and certainly for ultimate large-scale applications. The utility of interferometric lithography is demonstrated to applications in nanophotonics and nanofluidics. For nanophotonics, metamaterial fabrication, negative index metamaterials and plasmonic applications are discussed. Two approaches to the fabrication of nanofluidic structures: etching and oxidation of silicon substrates, and colloidal deposition of silica nanoparticles to form porous walls and roofs followed by calcination to remove the photoresist and sinter the particles. These later structures have evident biomimetic functionality.

Effectiveness of multi-shape laser surface texturing in the reduction of friction under lubrication regime

2016 ◽  
Vol 68 (1) ◽  
pp. 116-124 ◽  
Author(s):  
Dawit Zenebe Segu ◽  
Pyung Hwang
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Content Type ◽  
Laser Ablation Process ◽  
Specific Formula ◽  
Steel Surfaces ◽  
Lubrication Conditions

Purpose – The purpose of this paper is to investigate and discuss the effect of multi-shape laser surface texturing (LST) steel surfaces on tribological performance. Design/methodology/approach – The textured surface with some specific formula arrays was fabricated by laser ablation process by combining patterns of circles and triangles, circles and squares and circles and ellipses. The tribological test was performed by a flat-on-flat tribometer under dry and lubrication conditions, and results were compared with that of untextured surface. Findings – The results showed that the textured surface had better friction coefficient performance than the untextured surface due to hydrodynamic lubrication effect. Through an increase in sliding speed, the beneficial effect of LST performance was achieved under dry and lubrication conditions. Originality/value – This paper develops multi-shape LST steel surfaces for improving the friction and wear performance under dry and lubrication conditions.

COMBINED EFFECT OF MECHANICAL GROOVING AND STAIN-ETCHED SURFACE ON OPTICAL AND ELECTRICAL PROPERTIES OF CRYSTALLINE SILICON SUBSTRATES

2014 ◽  
Vol 21 (03) ◽  
pp. 1450041 ◽  
Author(s):  
AHMED ZARROUG ◽  
LOTFI DERBALI ◽  
RACHID OUERTANI ◽  
WISSEM DIMASSI ◽  
HATEM EZZAOUIA
Keyword(s):  
Crystalline Silicon ◽  
Light Trapping ◽  
Front Surface ◽  
Minority Carrier Lifetime ◽  
Combined Effect ◽  
Machining Process ◽  
Silicon Substrates ◽  
Textured Surface ◽  
Crystalline Silicon Solar Cell ◽  
Simple Method

This paper investigates the combined effect of mechanical grooving and porous silicon (PS) on the front surface reflectance and the electronic properties of crystalline silicon substrates. Mechanical surface texturization leads to reduce the cell reflectance, enhance the light trapping and augment the carrier collection probability. PS was introduced as an efficient antireflective coating (ARC) onto the front surface of crystalline silicon solar cell. Micro-periodic V-shaped grooves were made by means of a micro-groove machining process prior to junction formation. Subsequently, wafers were subjected to an isotropic potassium hydroxide ( KOH ) etching so that the V-shape would be turned to a U-shape. We found that the successive treatment of silicon surfaces with stain-etching, grooving then alkaline etching enhances the absorption of the textured surface, and decreases the reflectance from 35% to 7% in the 300–1200 nm wavelength range. We obtained a significant increase in the overall light path that generates the building up of the light trapping inside the substrate. We found an improvement in the illuminated I–V characteristics and an increase in the minority carrier lifetime τeff. Such a simple method was adopted to effectively reinforce the overall device performance of crystalline silicon-based solar cells.

Numerical and experimental study on the effect of surface texture with roughness orientation considered under a mixed lubrication state

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junru Wang ◽  
Quandai Wang ◽  
Yueyan Li ◽  
Meiling Guo ◽  
Pengyang Li ◽  
...  
Keyword(s):  
Surface Texture ◽  
Surface Texturing ◽  
Mixed Lubrication ◽  
Laser Surface ◽  
Geometric Parameters ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Asperity Contact ◽  
Content Type ◽  
Texture Parameters

Purpose The purpose of this paper is to investigate the effects of surface texture with roughness orientation considered on tribological properties under a mixed lubrication state numerically and experimentally. Design/methodology/approach Based on the average Reynolds equation and asperity contact model, the impacts of surface texture parameters and roughness orientation on lubrication properties have been calculated using finite difference method. Tin–bronze samples with various prescribed surface texture geometric parameters and roughness orientation were fabricated by laser surface texturing technique, and the tribology performance of the textured surface was studied experimentally. Findings The effects of surface geometric parameters and roughness orientation parameters have been discerned. The experimental observations are in good agreement with the numerical prediction, which suggests that the numerical scheme adopted in this work is suitable in capturing the surface texture and roughness effect under mixed lubrication state. Originality/value By meticulously controlling the surface roughness and surface texture geometric characteristics based on the laser surface texturing process, samples with prescribed surface texture parameters and roughness orientation consistent with that in theoretical studies were fabricated and the theoretical model and results were verified experimentally.

Defect Reduction and Defect Engineering in Silicon-on-Sapphire Material Using Ge Implantation

1990 ◽  
Vol 201 ◽  
Author(s):  
F. Namavar ◽  
E. Cortesi ◽  
N. M. Kalkhoran ◽  
J. M. Manke ◽  
B. L. Buchanan
Keyword(s):  
Leakage Current ◽  
Defect Density ◽  
Solid Phase ◽  
Substantial Reduction ◽  
Interface Region ◽  
Radiation Environment ◽  
Solid Phase Epitaxy ◽  
Defect Reduction ◽  
Radiation Induced

AbstractSubstantial reduction of defect density in silicon-on-sapphire (SOS) material is required to broaden its range of applications to include CMOS and bipolar devices. In recent years, solid phase epitaxy and regrowth (SPEAR) and double solid phase epitaxy (DSPE) processes were applied to SOS to reduce the density of defects in the silicon. These methods result in improved carrier mobilities, but also in increased leakage current, even before irradiation. In a radiation environment, this material has a large increase in radiation induced back channel leakage current as compared to standard wafers. In other words, the radiation hardness quality of the SOS declines when the crystalline quality of the Si near the sapphire interface is improved.In this paper, we will demonstrate that Ge implantation, rather than Si implantation normally employed in DSPE and SPEAR processes, is an efficient and more effective way to reduce the density of defects near the surface silicon region without improving the Si/sapphire interface region. Ge implantation may be used to engineer defects in the Si/sapphire interface region to eliminate back channel leakage problems.

Properties of large-area nanomagnet arrays with 100 nm period made by interferometric lithography

1999 ◽  
Vol 85 (8) ◽  
pp. 6160-6162 ◽  
Author(s):  
T. A. Savas ◽  
M. Farhoud ◽  
Henry I. Smith ◽  
M. Hwang ◽  
C. A. Ross
Keyword(s):  
Large Area ◽  
Interferometric Lithography

ATOMISTIC SCALE SIMULATION OF TEXTURED SURFACES ON DRY SLIDING FRICTION

2013 ◽  
Vol 37 (3) ◽  
pp. 927-936 ◽  
Author(s):  
Ming-Yuan Chen ◽  
Zheng-Han Hong ◽  
Te-Hua Fang ◽  
Shao-Hui Kang ◽  
Li-Min Kuo
Keyword(s):  
Sliding Friction ◽  
Surface Texturing ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Many Body ◽  
Embedded Atom ◽  
Modified Embedded Atom Method ◽  
Body Potential

Fe sliding on a Fe substrate with surface texturing is investigated using molecular dynamics simulation. The modified embedded-atom method many-body potential is used to describe the interaction of Fe atoms. The tribological properties of surface texturing during nanosliding are discussed. Results indicate that a textured surface has lower friction than that of a flat surface. In addition, a surface with parallel grooves has lower friction than that of a dimpled surface. Hence, surface texturing greatly affects friction.

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