Widening Absorption Band of Grating Structure With Complex Dual-Groove Grating

2011 ◽  
Author(s):  
Y. Jiao ◽  
L. H. Liu ◽  
P.-f. Hsu
Keyword(s):  
Far Infrared ◽  
Radiative Properties ◽  
Spectral Bandwidth ◽  
Grating Structure ◽  
Microstructured Surface ◽  
Rigorous Coupled Wave Analysis ◽  
Periodic Grating ◽  
Novel Structure ◽  
Rigorous Coupled Wave ◽  
Rectangular Groove

The wavelength-selective radiative properties are becoming noticeable requirements in various technological fields. There have been many researches focus on the radiative properties of periodic microstructured surface of metals. However, the spectral bandwidth of high absorptance is often too narrow by applying the conventional grating structures. In order to solve this problem, in this paper we propose two novel periodic grating structures, which can widen the spectral bandwidth of high absorptance. One of the new periodic grating structures, called dual-groove grating, is constructed by adding a rectangular groove at the bottom of the simple binary grating’s groove through a secondary microscale processing. The other novel grating structure, which is called complex dual-groove grating, is constructed by superposing a dual-groove grating and a simple binary grating within one period. Aluminum grating structure is taken as an example to show how the geometric parameters based on the novel structure widen the spectral bandwidth of high absorptance within mid-infrared and far-infrared spectra. The rigorous coupled-wave analysis (RCWA) is used to calculate the absorptance of periodic grating structures. The results show that, two close absorption peaks and three connecting absorption peaks are obtained respectively for the two novel periodic grating structures. These two novel structures may widen the effective spectral bandwidth of high absorptance of the microscale periodic grating structures.

Widening Absorption Band of Grating Structure With Complex Dual-Groove Grating

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Y. Jiao ◽  
L. H. Liu ◽  
P.-F. Hsu
Keyword(s):  
Far Infrared ◽  
Radiative Properties ◽  
Effective Bandwidth ◽  
Grating Structure ◽  
Rigorous Coupled Wave Analysis ◽  
Periodic Grating ◽  
Rigorous Coupled Wave ◽  
Rectangular Groove ◽  
Far Infrared Spectra ◽  
High Absorption

The wavelength-selective radiative property is becoming a noticeable requirement in various technological fields. There are many researches that have been focused on the radiative properties of metal periodic microstructure surface. However, the spectral bandwidth of high absorptance is often too narrow if excited by the conventional grating structures. In order to solve this problem, two novel periodic grating structures are proposed in this paper, which can increase the effective bandwidth of high absorption peaks. One of the new periodic grating structures, called dual-groove grating, is constructed by adding a rectangular groove at the bottom of the simple grating's groove through a secondary microscale processing. The other grating structure, which is called complex dual-groove grating, is constructed by superposing a dual-groove grating with a simple grating within one period. Aluminum grating structure is taken as an example to show the advantage of proposed structures on increasing effective bandwidth of high absorption peaks within mid-infrared and far-infrared spectra. The rigorous coupled-wave analysis (RCWA) is used to calculate the absorptance of periodic grating structures. The results shows that, two close absorption peaks and three connecting absorption peaks are obtained respectively for the two periodic grating structures. The effective bandwidth of high absorption peaks within interested wavelength band is improved obviously by these two microscale grating structures.

Radiative Properties of Pattered Wafers With Linewidth Below 100 nm

2005 ◽  
Author(s):  
Y.-B. Chen ◽  
Z. M. Zhang ◽  
P. J. Timans
Keyword(s):  
Periodic Structures ◽  
Numerical Study ◽  
Radiative Properties ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Recent Developments ◽  
Effective Medium Approach ◽  
Rigorous Coupled Wave ◽  
Very High

Temperature nonuniformity is a critical problem in rapid thermal processing (RTP) of wafers because it leads to uneven diffusion of implanted dopants and introduces thermal stress that can produce defects. One cause of the problem is nonuniform absorption of thermal radiation, especially in patterned wafers, where the optical properties vary across the surface of the wafer. Recent developments in RTP have lead to the use of millisecond-duration heating cycles, where light with very high power density is used to heat the surface of the wafer. Pattern effects are especially important here, because there is very little time for thermal diffusion to even out temperature distributions during the heating cycle. There have been very few studies on the radiative properties of patterned wafers, especially for the structures expected to be used on advanced semiconductor devices. The feature size is already below 100 nm and is comparable or smaller than the wavelengths of radiation (200–1000 nm) emitted by the flash-lamps typically used for millisecond processing. Hence, this work is devoted to a parametric numerical study of the radiative properties of patterned wafers with the smallest dimension down to 30 nm. The effects of wavelength, wave polarization, and angle of incidence on selected periodically patterned wafers are presented. The methods include the rigorous coupled wave analysis (RCWA) and the effective medium approach (EMA). RCWA is used to obtain exact solutions of Maxwell’s equations, and EMA is used to approximate the periodic structures as a planar multilayer structure with an effective dielectric function. This study provides an assessment of the applicability of EMA for simulations of radiative properties of patterned wafers.

Impact of Nanoscale Features of Metallic Slits on Mid-Infrared Radiative Properties

2008 ◽  
Author(s):  
Y.-B. Chen ◽  
J.-S. Chen ◽  
K. Fu ◽  
P.-F. Hsu
Keyword(s):  
Physical Mechanism ◽  
Radiative Properties ◽  
Cavity Resonance ◽  
Mid Infrared ◽  
Rigorous Coupled Wave Analysis ◽  
Slit Geometry ◽  
Rigorous Coupled Wave ◽  
Nanoscale Features ◽  
Poynting Vectors ◽  
Difference Time

Mid-Infrared radiative properties (absorptance, reflectance, and transmittance) of submicron gold slit arrays have been numerically studied with rigorous coupled-wave analysis and the finite difference time domain method. The slit width varies from 50 nm to 300 nm and a square feature may attach at either or both slit sides. Although the wavelength is one or two orders of magnitude longer than the side length of features, the attached nanoscale features can modify radiative properties significantly. Directional dependence on radiative properties has also been detail investigated by looking into electromagnetic fields and Poynting vectors of selected slit geometry. One possible physical mechanism, cavity resonance, account for unique radiative properties have been suggested and verified in the study as well.

Impacts of Nanoscale Features on Infrared Radiative Properties of Metallic Slit Arrays

2009 ◽  
Author(s):  
Y.-B. Chen ◽  
J.-S. Chen ◽  
P.-F. Hsu
Keyword(s):  
Transverse Magnetic ◽  
Radiative Properties ◽  
Cavity Resonance ◽  
Resonance Excitation ◽  
Angle Of Incidence ◽  
Resonance Modes ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Nanoscale Features ◽  
Poynting Vectors

Radiative properties (absorptance, reflectance, and transmittance) of deep slits with five nanoscale slit profile variations at the transverse magnetic wave incidence are numerically investigated in this work by employing the rigorous coupled-wave analysis. For slits with attached features, their radiative properties can be much different due to the modified cavity geometry and dangled structures, even at wavelengths between 3 and 15 μm. The shifts of cavity resonance excitation result in higher transmittance through narrower slits at specific wavelengths and resonance modes are confirmed with the electromagnetic fields. Opposite roles possibly played by features in increasing or decreasing absorptance are determined by the feature position and demonstrated by Poynting vectors. Correlations among all properties of a representative slit array, the angle of incidence, and the slit density are also comprehensively studied.

Study of the Absorptance of Si-gratings and of arrays of SiO2-filled trenches on Si-grating substrate

2016 ◽  
Vol 12 (2) ◽  
pp. 4278-4290
Author(s):  
Faouzi Ghmari ◽  
Ilhem Mezni
Keyword(s):  
Transverse Electric ◽  
Transverse Magnetic ◽  
Radiative Properties ◽  
Geometrical Parameters ◽  
Perfect Absorber ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Model Structures

The purpose of this paper is to study the radiative properties of two model structures. The first model (A-1) is a rectangular grating of silicon (Si). The second one (A-2) is obtained from A-1 by filling their trenches by SiO2. These patterned wafers are characterized by three geometrical parameters, the period d, the filling factorand the thickness h. To derive and compute the radiative properties we use a rigorous coupled wave analysis (RCWA) method. Our attention is focused on the absorptance of these structures when they are illuminated by a monochromatic plane wave. We investigate the effect of the filling factor on the absorptance versus the direction of the incident wave. At specific angles of incidence the effect of the period is also studied. Besides, the influence of the thickness h on the absorptance is included throughout this work. At the wavelength = 632,8nm, we especially show that we can identify several perfect absorber model structures characterized by specific parameters and by accurate angle of incidence. We show that this will be done in both transverse electric (TE) and transverse magnetic (TM) polarization cases.

Modeling Infrared Radiative Properties of Heavily Doped Silicon Complex Gratings With Geometric Modifications

2009 ◽  
Author(s):  
Ai-Hua Wang ◽  
Pei-feng Hsu ◽  
Yu-Bin Chen ◽  
Lin-Hua Liu
Keyword(s):  
Radiative Properties ◽  
Cavity Resonance ◽  
Resonance Excitation ◽  
Rigorous Coupled Wave Analysis ◽  
Doped Silicon ◽  
Heavily Doped ◽  
Rigorous Coupled Wave ◽  
Nanoscale Features ◽  
Difference Time ◽  
Plasmon Polaritons

Based on the prior work by authors, radiative properties of modified complex gratings with nanoscale features are studied. The purpose of this work is to demonstrate, even preliminary, the possibility of using complex gratings and nanoscale surface features to modify far field radiative properties. A finite-difference time-domain numerical scheme was used to model the infrared radiative properties of heavily doped silicon simple and complex gratings. The solutions were validated with those of rigorous coupled-wave analysis method. By properly choosing the carrier concentration and geometry, silicon complex gratings exhibit a broadband absorptance peak resulting from the excitation of surface plasmon polaritons. Meanwhile, the absorptance of four modified complex gratings with attached features has been numerically investigated for the impacts of the attached structures. Firstly, though absorptance spectra of gratings almost remain unchanged, their locations shift towards longer wavelengths. Secondly, the spectral absorptance peak of two modified complex gratings is wider than that of gratings without attached features due to the cavity resonance excitation. Thirdly, the spectral absorptance of complex gratings with square features in three sizes was compared and shows that the peak wavelength shifts toward longer wavelengths with enlarged feature size.

Radiative Properties of Patterned Wafers With Nanoscale Linewidth

2006 ◽  
Vol 129 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Y.-B. Chen ◽  
Z. M. Zhang ◽  
P. J. Timans
Keyword(s):  
Numerical Solutions ◽  
Radiative Properties ◽  
Wafer Surface ◽  
Angle Of Incidence ◽  
Patterned Wafers ◽  
Rigorous Coupled Wave Analysis ◽  
Recent Developments ◽  
Effects Of Temperature ◽  
Rigorous Coupled Wave ◽  
Feature Dimension

Abstract Temperature nonuniformity is a critical problem in rapid thermal processing (RTP) of wafers because it leads to uneven diffusion of implanted dopants and introduces thermal stress. One cause of the problem is nonuniform absorption of thermal radiation, especially in patterned wafers, where the optical properties vary across the wafer surface. Recent developments in RTP have led to the use of millisecond-duration heating cycle, which is too short for thermal diffusion to even out the temperature distribution. The feature size is already below 100nm and is smaller than the wavelength (200-1000nm) of the flash-lamp radiation. Little is known to the spectral distribution of the absorbed energy for different patterning structures. This paper presents a parametric study of the radiative properties of patterned wafers with the smallest feature dimension down to 30nm, considering the effects of temperature, wavelength, polarization, and angle of incidence. The rigorous coupled wave analysis is employed to obtain numerical solutions of the Maxwell equations and to assess the applicability of the method of homogenization based on effective medium formulations.

Measurement of Coherent Thermal Emission From Subwavelength Grating Structures by the Excitation of Magnetic Polaritons

2012 ◽  
Author(s):  
L. P. Wang ◽  
Z. M. Zhang
Keyword(s):  
Elevated Temperatures ◽  
Thermal Emission ◽  
Infrared Region ◽  
Radiative Properties ◽  
Scattering Rate ◽  
Rigorous Coupled Wave Analysis ◽  
Space Cooling ◽  
Dielectric Spacer ◽  
Magnetic Polaritons ◽  
Rigorous Coupled Wave

Tailoring radiative properties such as spectral control of thermal emission is beneficial in many applications such as space cooling and energy harvesting. The effect of magnetic polaritons (MPs) on spectral modulation has been analyzed previously and shown to exhibit omnidirectional behaviors when magnetic polaritons are excited in metallic grating structures with a dielectric spacer on a metallic film. The present work provides an experimental demonstration of coherent thermal emission from such a microstructure in the infrared region at both room and elevated temperatures. Samples with different patterns are fabricated to study the geometric effect on the MPs. The emittance at elevated temperatures is directly measured using a home-built emissometer, while the room-temperature emittance is indirectly obtained from the reflectance measurements. The rigorous coupled-wave analysis and the LC model are employed to elucidate the mechanisms, by incorporating the Drude model with a temperature-dependent scattering rate.

Infrared Radiative Properties of Submicron Metallic Slit Arrays

2007 ◽  
Author(s):  
Y.-B. Chen ◽  
B. J. Lee ◽  
Z. M. Zhang
Keyword(s):  
Fourier Transform ◽  
Effective Medium Theory ◽  
Radiative Properties ◽  
Silicon Substrates ◽  
Wave Analysis ◽  
Medium Theory ◽  
Rigorous Coupled Wave Analysis ◽  
Infrared Spectrometer ◽  
Metallic Slit ◽  
Rigorous Coupled Wave

Submicron metallic slit arrays with different geometry were designed and fabricated on silicon substrates. Their infrared radiative properties (transmittance, reflectance, and absorptance) were investigated both experimentally and theoretically. The normal transmittance of three fabricated Au slit arrays was measured at wavelengths between 2 and 15 μm using a Fourier-transform infrared spectrometer. The experiment results were compared with the values calculated from the rigorous coupled-wave analysis. The applicability of the effective medium theory for modeling radiative properties was also examined. The agreement between the measurement and modeling results demonstrates the feasibility of quantitative tuning of the radiative properties by employing periodic micro/nanostructures.

scholarly journals Effects of Measurement Configurations on the Sensitivity of Morpho Butterfly Scales Based Chemical Biosensor

2022 ◽  
Vol 9 ◽  
Author(s):  
Zhengqiong Dong ◽  
Hang Zhao ◽  
Lei Nie ◽  
Shaokang Tang ◽  
Chenyang Li ◽  
...  
Keyword(s):  
Ambient Medium ◽  
Incident Angle ◽  
Azimuthal Angle ◽  
Detection Sensitivity ◽  
Butterfly Wing ◽  
Rigorous Coupled Wave Analysis ◽  
Rigorous Coupled Wave ◽  
Rectangular Groove ◽  
Morpho Butterfly ◽  
Selection Of

The Morpho butterfly wing with tree-shaped alternating multilayer is an effective chemical biosensor to distinguish between ambient medium, and its detection sensitivity is inextricably linked to the measurement configuration including incident angle, azimuthal angle, and so on. In order to reveal the effects and the selection of measurement configuration. In this work, the model of the Morpho butterfly wing is built using the rigorous coupled-wave analysis method by considering its profile is a rectangular-groove grating. On basis of the above model, the reflectivity of different diffraction orders at a different incident angle and azimuthal angle is calculated, and the influence of incident angle and azimuthal angle on performance of Morpho butterfly scales-based biosensor is analyzed. The optimal incident angle at each azimuthal angle is given according to the proposed choice rule, then the azimuthal angle and the corresponding incident angle can be selected further.

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