Browsing by Author "Wang, H. W."

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A High Efficiency Field Emitters Pt/Si-nanocones Array with Vertically Aligned Structure
(2015-01-01)
Kao, P. H.
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Tai, H. M.
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Wang, H. W.
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Chiang, T. Y.
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Juang, J. Y.
An effective method of fabricating vertically aligned silicon nanocones (Si-NCs) was realized by using the self-assembled silver (Ag) nanoislands as natural metal-nanomask during dry etching process. The obtained Si-NCs were preferentially aligned along the c-axis direction. To enhance the field emission property, thin platinum (Pt) films (similar to 20 nm) were subsequently deposited on the Si-NCs by sputter coater to form Pt/Si-NCs heterostructures. The turn-on field defined by the 1 mu A/cm(2) current density criterion is similar to 2.85 V/mu m. As measurements of field emission, the low turn-on field was attributed to the vertical one-dimensional nanostructures, and perhaps more importantly, proper density distribution of the Pt/Si-NCs. The suggesting an interesting alternative route for producing Si-NCs that might be useful for optical and electronic applications.
Conversion Efficiency Enhancement of GaN/In(0.11)Ga(0.89)N Solar Cells With Nano Patterned Sapphire and Biomimetic Surface Antireflection Process
(2011-09-15)
Wang, H. W.
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Chen, H. C.
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Chang, Y. A.
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Lin, C. C.
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Han, H. W.
In this study, p-i-n double-heterojunction GaN/In(0.11)Ga(0.89)N solar cells grown by metal-organic chemical vapor deposition on pattern sapphire substrate are presented. The solar cell with standard process has a conversion efficiency of 3.1%, which corresponds to a fill factor of 58%, short circuit current density of 2.86 mA/cm(2), and open circuit voltage of 1.87 V under AM1.5G illumination. To further improve the conversion efficiency of the GaN/In(0.11)Ga(0.89)N solar cells, two-dimensional polystyrene nanospheres were deposited and self-organized as mask in the anisotropic inductively coupled plasma reactive ion etching process to form a biomimetic surface roughing texture. The surface morphology of the solar cell shows a periodically hexagonal bead pattern and the beads are formed in a diameter of 160 nm with a period of 250 nm. An increase of 15% in short circuit current density is found, thus improving the conversion efficiency to 3.87%. If we optimize the structure for 180 nm of the height and 375 nm of the period, a 10% gain can be expected when compared to the current structure.
Conversion Efficiency Enhancement of GaN/In0.11Ga0.89N Solar Cells With Nano Patterned Sapphire and Biomimetic Surface Antireflection Process
(2011-09-15)
Wang, H. W.
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Chen, H. C.
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Chang, Y. A.
;
Lin, C. C.
;
Han, H. W.
In this study, p-i-n double-heterojunction GaN/In0.11Ga0.89N solar cells grown by metal-organic chemical vapor deposition on pattern sapphire substrate are presented. The solar cell with standard process has a conversion efficiency of 3.1%, which corresponds to a fill factor of 58%, short circuit current density of 2.86 mA/cm(2), and open circuit voltage of 1.87 V under AM1.5G illumination. To further improve the conversion efficiency of the GaN/In0.11Ga0.89N solar cells, two-dimensional polystyrene nanospheres were deposited and self-organized as mask in the anisotropic inductively coupled plasma reactive ion etching process to form a biomimetic surface roughing texture. The surface morphology of the solar cell shows a periodically hexagonal bead pattern and the beads are formed in a diameter of 160 nm with a period of 250 nm. An increase of 15% in short circuit current density is found, thus improving the conversion efficiency to 3.87%. If we optimize the structure for 180 nm of the height and 375 nm of the period, a 10% gain can be expected when compared to the current structure.
EFFICIENCY ENHANCEMENT IN SINGLE JUNCTION INGAP SOLAR CELLS BY USING SELF-ASSEMBLED NANOSPHERES
(2010)
Chen, H. C.
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Tsai, Y. L.
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Wang, H. W.
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Tsai, M. A.
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Tseng, P. C.
A single-junction InGaP solar cells with polystyrene (PS) nanospheres on the surface has been developed. The self-assembly of PS nanospheres is one of the simplest and the fastest methods with which to build a 20 closely packed periodic structure. Based on the scattering of the PS nanospheres, the light path length can be increased. As compared to the InGaP solar cells without PS nanospheres on the top surface the standard process. An increase short-circuit current form 8.93% to 10.31% is improved when a single-junction InGaP solar cells with PS nanospheres. The conversion efficiency measured can also be improved from 8.79% to 9.71%. The single-junction InGaP solar cell with PS nanospheres was achieved.
Efficiency Enhancement in Single-Junction InGaP Solar Cells by Using Self-Assembled Nanospheres
(2011-06-01)
Chen, H. C.
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Lin, C. C.
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Wang, H. W.
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Tsai, M. A.
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Tseng, P. C.
A single-junction InGaP solar cell with polystyrene (PS) nanospheres on the surface has been developed. The self-assembly of PS nanospheres is one of the simplest and the fastest methods with which to build a 2-D closely packed periodic structure. Due to the scattering of the PS nanospheres, the light path length can be increased when compared to the InGaP solar cells without PS nanospheres on the top. An increase short-circuit current from 8.93 to 10.31 mA is improved when a single-junction InGaP solar cell is coated with PS nanospheres. The conversion efficiency measured can also be improved from 8.79% to 9.71%. The single-junction InGaP solar cell with PS nanospheres was achieved.
EFFICIENCY ENHANCEMENT InGaP/GaAs DUAL-JUNCTION SOLAR CELL WITH SUB-WAVELENGTH ANTIREFLECTION NANOROD ARRAYS
(2010)
Wang, H. W.
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Tsai, M. A.
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Chen, H. C.
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Tsai, Y. L.
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Tseng, P. C.
The enhanced conversion efficiency of the InGaP/GaAs dual-junction solar cell was demonstrated antireflection nanorod arrays. After self-assembled Ni clusters, the nanorod arrays were fabricated by inductively-coupled-plasma reactive ion etching. The conversion efficiency were measured under one-sun air mass 1.5 global illuminations at room temperature. The short current of the nanorod arrays cell was enhanced 10.0% and the efficiency was enhanced 10.8%. We were also studied the light absorption efficiencies of the top InGaP and bottom GaAs cells under the influence of nanorod arrays. Surface nanorod arrays were not only as antireflection layers but also scattering sources. The nanorod arrays structure can be significant improved the maximum conversion efficiency.
Embedded PUF on 14nm HKMG FinFET Platform: A Novel 2-bit-per-cell OTP-based Memory Feasible for IoT Secuirty Solution in 5G Era
(2019-01-01)
Hsieh, E. R.
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Wang, H. W.
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Liu, C. H.
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Chung, Steve S.
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Chen, T. P.
In this work, a novel concept of 2-bit-per-cell (2B/C) is introduced to realize high-density OTP PUF from a new scheme of dielectric breakdown. This PUF shows 10(5)x of large window, good immunity to high-temperature disturbance, and excellent retention under 150 degrees C baking, which are particularly for automotive applications. In terms of security. this PUF exhibits near ideal normal distribution of hamming distance and narrow distribution of hamming weight. The bit error rates are low, 0.78% at 25 degrees C and 1.95% at 150 degrees C, benchmarked on a 256-bit array. Finally, the security test of this PUF against the hackers' attack from the machine learning process has been proved to have high security. Overall, the proposed 2B/C OTP PUF demonstrated great potential for IoT security in 5G era.
LARGE-SCALE AND ENHANCED EFFICIENCY C-SI SOLAR CELL WITH MOTH-EYE-LIKE BY USING SELF-ASSEMBLED LITHOGRAPHY
(2010)
Tsai, M. A.
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Chen, H. C.
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Wang, H. W.
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Tsai, Y. L.
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Tseng, P. C.
We demonstrated the Si solar cell with ladder-shaped nanorod array, fabricated by combined the self-assembled lithography and reactive-ion etching technique. The measurement of angular reflective spectrums of the solar cell with ladder-shaped nanorod array using an integration sphere remained lower at broadband spectra and large angle of incident compared to the solar cell with micro-textured surface. The I-V measurement shown the current density and conversion efficiency could be improved by the ladder-shaped nanorod array. The enhancement conversion efficiency approached to 34.54%.