Browsing by Author "Sun, Kien-Wen"

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Effect of Etching Depth on Threshold Characteristics of GaSb-Based Middle Infrared Photonic-Crystal Surface-Emitting Lasers
(2019-03-14)
Li, Zong-Lin
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Lin, Shen-Chieh
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Lin, Gray
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Cheng, Hui-Wen
;
Sun, Kien-Wen
We study the effect of etching depth on the threshold characteristics of GaSb-based middle infrared (Mid-IR) photonic-crystal surface-emitting lasers (PCSELs) with different lattice periods. The below-threshold emission spectra are measured to identify the bandgap as well as band-edge modes. Moreover, the bandgap separation widens with increasing etching depth as a result of enhanced diffraction feedback coupling. However, the coupling is nearly independent of lattice period. The relationship between threshold gain and Bragg detuning is also experimentally determined for PCSELs and is similar to that calculated theoretically for one-dimensional distributed feedback lasers.
PCSEL Performance of Type-I InGaAsSb Double-QWs Laser Structure Prepared by MBE
(2019-01-02)
Cheng, Hui-Wen
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Lin, Shen-Chieh
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Li, Zong-Lin
;
Sun, Kien-Wen
;
Lee, Chien-Ping
This paper discusses the issue of controlling the epitaxial growth of mixed group V alloys to form a type-I InGaAsSb/AlGaAsSb double quantum wells (QWs) structure. We also discuss the run-to-run reproducibility of lattice-matched AlGaAsSb alloys and strained In0.35Ga0.65As0.095Sb0.905 in terms of growth parameters (V/III ratio, Sb-2/As-2 ratio). Molecular beam epitaxy (MBE) was used to grow two type-I InGaAsSb double-QWs laser structures differing only in the composition of the bottom cladding layer: Al0.85Ga0.15As0.072Sb0.928 (sample A) and Al0.5Ga0.5As0.043Sb0.957 (sample B). Both samples were respectively used in the fabrication of photonic crystal surface-emitting lasers (PCSELs). Sample A presented surface lasing action from circular as well as triangular photonic crystals. Sample B did not present surface lasing due to the deterioration of the active region during the growth of the upper cladding. Our findings underline the importance of temperature in the epitaxial formation of AlxGa1-xAsySb1-y in terms of lasing performance.
Self-assembled molecular magnets on patterned silicon substrates
(2006)
Chang, Chia-Ching
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Sun, Kien-Wen
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Lee, Shang-Fan
;
Kan, Lou-Sing
;
Kuan, Chieh-Hsiung
The paper reports the methods of preparing molecular magnets and pattering of the molecules on semiconductor surface. A highly magnetically aligned metallothionein containing Mn and Cd (Mn,Cd-MT-2) was first synthesized. Those molecules were then placed into nanopores prepared on silicon (001) surfaces using electron beam lithography and reactive ion etching techniques. We have observed self-assemble growth of those MT molecules on the patterned Si surface. The MT molecules have grown into rod or ring type nanostructures, depending on the patterned nanostructures on the surface. We also provide scanning electron microscopy (SEM) and atomic force microscopy (AFM) studied of those molecular nanostructures. This engineered molecule shows molecular magnetization and is biocompatible with conventional semiconductors. These features make Mn,Cd-MT-2 a good candidate for biological applications and sensing sources of new nano-devices.
Synthesis and characterization of a novel siloxane-imide-containing polybenzoxazine
(2011-03-01)
Chen, Kai-Chi
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Li, Hsun-Tien
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Chen, Wen-Bin
;
Liao, Chun-Hsiung
;
Sun, Kien-Wen
A novel siloxane-imide-containing polybenzoxazine based on N,N'-bis(N-phenyl-3,4-dihydro-2H-benzo[1,3]oxazine)-5, 5'-bis(1,1',3,3'-tetramethyldisiloxane-1,3-diyl)-bis(norborane-2,3-dicarboximide) (BZ-A1) was successfully synthesized. The thermal properties of BZ-A1 are superior to those of conventional polybenzoxazines lacking siloxane groups. Polymerized BZ-A1 possesses extremely low surface free energy (gamma(s) = 15.1 mJ m(-2)) after curing at 230 degrees C for 1 h. Moreover, the surface free energy of polymerized BZ-A1 is more stable than conventional bisphenol A-type polybenzoxazine during thermal curing and annealing processes, indicating that polymerized BZ-A1 is more suitable for applications requiring low surface free energy materials for high temperatures over long periods of time. (C) 2010 Society of Chemical Industry
Synthesis and performance enhancement of novel polybenzoxazines with low surface free energy
(2011-07-01)
Chen, Kai-Chi
;
Li, Hsun-Tien
;
Huang, Shu-Chen
;
Chen, Wen-Bin
;
Sun, Kien-Wen
A new siloxane-imide-containing benzoxazine, BZ-A6, has been successfully synthesized. The thermal properties of the polybenzoxazine (PBZ) prepared from BZ-A6 (PBZ-A6) are superior to those of conventional PBZs lacking siloxane groups. The normally brittle PBZs are toughened significantly as a result of adding siloxane-imide moieties. Moreover, the thermal and UV stabilities of the surface free energy of PBZ-A6 are dramatically improved over the conventional bisphenol-A-type PBZ. Siloxane-imide PBZs are more suitable for application as low-surface-free-energy materials that are highly resistant to temperature and UV radiation. PBZ-A6 may also be useful in weather-resistant and self-cleaning coating materials because of its low surface free energy and good thermal and UV resistance. (C) 2011 Society of Chemical Industry