Browsing by Author "Lin, Men-Ku"

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Design and Fabrication of Sub-Wavelength Structure on Silicon Nitride for Solar Cells
(2009)
Sahoo, Kartika Chandra
;
Li, Yiming
;
Lin, Men-Ku
;
Chang, Edward Yi
;
Huang, Jin-Hua
In this study, we explore the spectral reflectivity of pyramid-shaped silicon nitride (Si3N4) sub-wavelength structures (SWS). First, a multilayer rigorous coupled-wave approach is advanced to investigate the reflection properties of Si3N4 SWS. We first optimize Si3N4 SWS structure for the best effective reflectance properties. The results of our study show that a lowest effective reflectivity of 1.77% can be obtained for the examined Si3N4 SWS with the height of etched part of Si3N4 and the thickness of non-etched layer of 150 nm and 70 nm. Then, we develop a simple and scalable approach for fabricating SWS on silicon nitride by means of self-assembled nickel nano particle masks and inductively coupled plasma ion etching. Silicon nitride SWS surfaces with diameter of 120 nm - 180 nm and a height of 150 nm - 160 nm were obtained for lowest average reflectivity for wavelength range from 190 nm to 1000 nm. A low reflectivity below 1% was observed over wavelength from 600 to 800 nm. The measured reflectivity is closely matched with the simulated results. Using the measured reflectivity data, the solar cell characteristics has further been compared for single layer antireflection coatings and SWS structures and a 1.31% improvement in efficiency was observed.
Fabrication and Configuration Development of Silicon Nitride Sub-Wavelength Structures for Solar Cell Application
(2010-09-01)
Sahoo, Kartika Chandra
;
Chang, Edward Yi
;
Li, Yiming
;
Lin, Men-Ku
;
Huang, Jin-Hua
To replace the double layer antireflection coating and improve the efficiency of solar cell, a self assembled nickel nano particle mask followed by inductively coupled plasma (ICP) ion etching method is proposed to form the sub-wavelength structures (SWS) on silicon nitride (Si(3)N(4)) antireflection coating layers instead of semiconductor layer. The size and density of nickel nano particles can be controlled by the initial thickness of nickel film that is annealed to form the nano-particles on the Si(3)N(4) film deposited on the silicon substrate. ICP etching time is responsible for controlling the height of the fabricated Si(3)N(4) SWS on silicon substrate, which is seen from our experiment. It is found that the lowest average reflectivity of 3.12% for wavelength ranging from 350 to 1000 nm is achieved when the diameter and height of the SWS are 120-180 nm and 150-160 nm, respectively. A low reflectance below 1% is observed over the wavelength from 590 to 680 nm for the fabricated Si(3)N(4) SWS on silicon subs. The efficiency of Si(3)N(4) SWS could be improved by 1.31%, compared with the single layer anti-reflection (SLAR) coatings of Si(3)N(4), using PC1D program. The results of this study may benefit the fabrication of solar cells.
Fabrication of Antireflective Sub-Wavelength Structures on Silicon Nitride Using Nano Cluster Mask for Solar Cell Application
(2009-07-01)
Sahoo, Kartika Chandra
;
Lin, Men-Ku
;
Chang, Edward-Yi
;
Lu, Yi-Yao
;
Chen, Chun-Chi
We have developed a simple and scalable approach for fabricating sub-wavelength structures (SWS) on silicon nitride by means of self-assembled nickel nanoparticle masks and inductively coupled plasma (ICP) ion etching. Silicon nitride SWS surfaces with diameter of 160-200 nm and a height of 140-150 nm were obtained. A low reflectivity below 1% was observed over wavelength from 590 to 680 nm. Using the measured reflectivity data in PC1D, the solar cell characteristics has been compared for single layer anti-reflection (SLAR) coatings and SWS and a 0.8% improvement in efficiency has been seen.
Reflectance of Sub-Wavelength Structure on Silicon Nitride for Solar Cell Application
(2009)
Sahoo, Kartika Chandra
;
Li, Yiming
;
Chang, Edward Yi
;
Lin, Men-Ku
;
Huang, Jin-Hua
In this study, reflection properties of sub-wavelength structures (SWS) on silicon nitride (Si(3)N(4)) antireflective coatings are investigated. Numerical calculation of SWS reflection based on a rigorous coupled-wave approach is conducted and compared with the measurement of fabricated samples. We compare the results of single- and double-layer-antireflection (SLAR and DLAR) coatings with SWS on Si(3)N(4), taking into account average residual reflectivity over a range of wavelengths, where the solar efficiency is further estimated. A low average residual reflectivity of 9.56% could be obtained for a Si(3)N(4) SWS height and non-etched layer of 140 nm and 60 nm respectively, which will be less than 80 nm Si(3)N(4) SLAR (similar to 15%) and almost the same as that of a DLAR with 60 nm Si(3)N(4) and 70 nm magnesium fluoride (similar to 10%).
Silicon Nitride Nanopillars and Nanocones Formed by Nickel Nanoclusters and Inductively Coupled Plasma Etching for Solar Cell Application
(2009-12-01)
Sahoo, Kartika Chandra
;
Lin, Men-Ku
;
Chang, Edward-Yi
;
Tinh, Tran Binh
;
Li, Yiming
The external quantum efficiency of solar cells can be improved by using textured surface with minimum reflection. We have fabricated nanopillars and nanocone structures on silicon nitride surface by means of self-assembled nickel nano particle masks with single step inductively coupled plasma (ICP) ion etching and double step ICP etching, respectively. Thus, sub-wavelength nanopillar and nanocone-like structures displaying low reflectance were obtained readily without the need for any lithography equipment. The formation mechanism of nanopillar and nanocone like structures fabricated on silicon nitride surface has been discussed. The relationship of etching time with structure height and average reflectance spectra has been drawn. (C) 2009 The Japan Society of Applied Physics