Wen-Hsi Lee

Prof. Wen-Hsi Lee

Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 October 2014 in Polymers
Verified
Journal Article
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PKPrabakaran Kumaresan
Prabakaran Kumaresan
SVSureshraju Vegiraju
Sureshraju Vegiraju
YEYamuna Ezhumalai
Yamuna Ezhumalai
SYShueh Lin Yau
Shueh Lin Yau
Choongik KimChoongik Kim
Choongik Kim
MCMing-Chou Chen
Ming-Chou Chen
Organic photovoltaics (OPVs) and dye-sensitized solar cells (DSSCs) have drawn great interest from both academics and industry, due to the possibility of low-cost conversion of photovoltaic energy at reasonable efficiencies. This review focuses on recent progress in molecular engineering and technological aspects of fused-thiophene-based organic dye molecules for applications in solar cells. Particular attention has been paid to the design principles and stability of these dye molecules, as well as on the effects of various electrolyte systems for DSSCs. Importantly, it has been found that incorporation of a fused-thiophene unit into the sensitizer has several advantages, such as red-shift of the intramolecular charge transfer band, tuning of the frontier molecular energy level, and improvements in both photovoltaic performance and stability. This work also examines the correlation between the physical properties and placement of fused-thiophene in the molecular structure with regard to their performance in OPVs and DSSCs.

5 September 2007 in Journal of the American Ceramic Society
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Journal Article
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WLWen-Hsi Lee
Wen-Hsi Lee
CSChi‐Yi Su
Chi‐Yi Su

23 July 2020 in IEEE Transactions on Electron Devices
Verified
Journal Article
Closed access
PSPo-Jung Sung
Po-Jung Sung
SCShu-Wei Chang
Shu-Wei Chang
KKKuo-Hsing Kao
Kuo-Hsing Kao
CWChien-Ting Wu
Chien-Ting Wu
CSChun-Jung Su
Chun-Jung Su
TCTien-Sheng Chao
Tien-Sheng Chao
In this study, conventional CMOS and complementary field-effect transistor (CFET) inverters based on a vertically stacked-nanosheet (NS) structure were fabricated. The NS below 8-nm channel layer thickness (TSi) was obtained by dry etching and wet etching processes. The channel thickness is controlled by dry etching, and the channel width was shrunk down by wet etching. Compared to single nanowire field-effect transistors (NSFETs), stacked NSFETs exhibit higher on-current performance. For the CMOS inverter, the voltage transfer characteristics (VTCs) could be matched much better by adjusting the channel widths and layers for N-channel MOSFET (NFET) and P-channel MOSFET (PFET), respectively. For the CFET inverter, layout areas could be reduced and requires less number of lithographic and ion implantation steps contrary to the CMOS inverter. However, we observe that the VTCs of the CFET inverters still show asymmetric behavior due to the difficulties of adjustment in NS layers and systematic behavior of threshold voltages for NFETs/PFETs. This work experimentally demonstrates the CMOS and CFET inverters on the vertically stacked NS structure, which is promising for system-on-panel (SoP) and 3-D-ICs applications.

25 January 2022 in IEEE Transactions on Electron Devices
Verified
Journal Article
Closed access
SCShu-Wei Chang
Shu-Wei Chang
TLTsung-Han Lu
Tsung-Han Lu
CYCong-Yi Yang
Cong-Yi Yang
CYCheng-Jui Yeh
Cheng-Jui Yeh
MHMin-Kun Huang
Min-Kun Huang
WYWen-Kuan Yeh
Wen-Kuan Yeh
In this article, heterogeneous complementary field-effect-transistor (CFET) constructed by vertically stacking amorphous indium gallium zinc oxide (a-IGZO) n-channel on poly-Si p-channel with their own dielectric layer and work function metal gate inverters were demonstrated. Meanwhile, high-frequency IGZO radio frequency (RF) devices with poly-Si as guard ring material simultaneously were fabricated in the same process. High ${f}_{\text {T}}$ and ${f}_{\text {max}}$ IGZO Radio Frequency Integrated Circuits (RFICs) with the excellent on–off ratio need to be promoted by introducing fluorine-based gas. For the IGZO device in CFET, its threshold voltage can be tuned by the adjusted gate for ideal inverter operation at different supply voltage ( ${V}_{\text {DD}}$ ). Moreover, the swing of the IGZO transistor and the gain extracted from voltage transfer characteristic (VTC) curves can also be improved when the controlled gate and adjusted gate are connected as an input terminal, but the ${V}_{\text {TH}}$ tunability for the inverter is satisfied in the meantime. We also simulated 6T-SRAM circuit by SPICE model to further investigate the potential of an adjusted gate for optimizing the noise margin during SRAM operation.

1 March 2019 in AIP Advances
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Journal Article
Open access
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KJKai-Jyun Jhong
Kai-Jyun Jhong
TCTsung-Wei Chang
Tsung-Wei Chang
WLWen-Hsi Lee
Wen-Hsi Lee
MTMi-Ching Tsai
Mi-Ching Tsai
IJI-Hua Jiang
I-Hua Jiang
In this paper, a soft magnetic composite (SMC) material, FeSiCr, is analyzed for its beneficial electromagnetic properties and unique 3D formation capacity, which endows a very high potential to become the material for electric motor fabrication by 3D printing technology adopting high temperature selective laser melting (SLM) process. A microscopic and spectroscopic experiment performed on FeSiCr after SLM process showed that FeO is the oxide layer responsible for the unique advantages of this material. Furthermore, FeSiCr is proved to have lower core loss and eddy current loss at high frequency via the comparison analysis between FeSiCr and silicon steel sheet, a popularly used material for electric motor construction.

2 March 2012 in Materials
Verified
Journal Article
Open access
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SCSheng-Wen Chen
Sheng-Wen Chen
YWYu-Sheng Wang
Yu-Sheng Wang
SHShao-Yu Hu
Shao-Yu Hu
WLWen-Hsi Lee
Wen-Hsi Lee
CCChieh-Cheng Chi
Chieh-Cheng Chi
YWYing-Lang Wang
Ying-Lang Wang
Amorphous nitrogen-doped silicon carbide (α-SiCN:H) films have been used as a Cu penetration diffusion barrier and interconnect etch stop layer in the below 90-nanometer ultra-large scale integration (ULSI) manufacturing technology. In this study, the etching stop layers were deposited by using trimethylsilane (3MS) or tetramethylsilane (4MS) with ammonia by plasma-enhanced chemical vapor deposition (PECVD) followed by a procedure for tetra-ethoxyl silane (TEOS) oxide. The depth profile of Cu distribution examined by second ion mass spectroscopy (SIMs) showed that 3MS α-SiCN:H exhibited a better barrier performance than the 4MS film, which was revealed by the Cu signal. The FTIR spectra also showed the intensity of Si-CH3 stretch mode in the α-SiCN:H film deposited by 3MS was higher than that deposited by 4MS. A novel multi structure of oxygen-doped silicon carbide (SiC:O) substituted TEOS oxide capped on 4MS α-SiC:N film was also examined. In addition to this, the new multi etch stop layers can be deposited together with the same tool which can thus eliminate the effect of the vacuum break and accompanying environmental contamination.