Browsing by Author "Wang, Jyh-Shyang"

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Effects of source and substrate temperatures on the properties of ITO/CuPc/C-60 heterostructure prepared by physical vapor deposition
(2008-04-01)
Chiu, Kuan-Cheng
;
Juey, Liu-Ting
;
Su, Chih-Feng
;
Tang, Shiow-Jing
;
Jong, Ming-Nan
Small-molecule organic photovoltaic (OPV) cells with a heterostructure of indium tin oxide (ITO)/copper phthalocyanine (CuPc)/C-60/Ag were fabricated by physical vapor deposition at different source temperatures T-sou and substrate temperatures T-sub. The physical properties of these as-deposited organic thin films including surface morphology, structural information, and electrical and optical properties were measured (in layer-by-layer sequence) by atomic force microscopy, X-ray diffraction, current-voltage characteristics, and electronic absorption spectra. At first, the effects of different deposition conditions (Tsou and Tsub) on growth rate and film thickness of these organic thin films were examined. Then, the interface properties of ITO/CuPc and CuPc/C-60 were studied with respect to T-sub. Short-circuit current density J(sc) and open-circuit voltage V c for this ITO/CuPc/C-60/Ag heterostructure under illumination were performed, and the spectral response of J(sc) was analyzed. Finally, the Tub-dependence of the physical properties of the as-deposited organic films and of the performance of the as-fabricated OPV cells were discussed. (c) 2007 Elsevier B.V. All rights reserved.
Evaluating the abrasive wear of Zn(1-x)Mn(x)O heteroepitaxial layers using a nanoscratch technique
(2010-08-01)
Chang, Yu-Ming
;
Wen, Hua-Chiang
;
Yang, Chu-Shou
;
Lian, Derming
;
Tsai, Chien-Huang
In this study, we used nanoscratch techniques under a ramping load to evaluate the abrasive wear of Zn(1-x)Mn(x)O epilayers (0 <= x <= 0.16) grown through molecular beam epitaxy (MBE) on sapphire substrates. We analyzed the surface roughness and damage using atomic force microscopy (AFM) and nano-indenter techniques. The scratched surfaces of the Zn(1-x)Mn(x)O epilayers were significantly different for the various Mn compositions. AFM imaging of the Zn(1-x)Mn(x)O films revealed that pileup phenomena were important on both sides of each scratch. During the scratching process, we found that cracking dominated in the case of Zn(1-x)Mn(x)O films while ploughing; also we observed lower values of the coefficient of friction and shallower penetration depths for the films upon increasing the Mn content (x) from 0 to 0.16, suggesting that higher Mn contents provided the Zn(1-x)Mn(x)O epilayers with higher shear resistances, enhanced by the presence of MnO bonds. (C) 2010 Elsevier Ltd. All rights reserved.
Evaluating the abrasive wear of Zn1-xMnxO heteroepitaxial layers using a nanoscratch technique
(2010-08-01)
Chang, Yu-Ming
;
Wen, Hua-Chiang
;
Yang, Chu-Shou
;
Lian, Derming
;
Tsai, Chien-Huang
In this study, we used nanoscratch techniques under a ramping load to evaluate the abrasive wear of Zn1-xMnxO epilayers (0 <= x <= 0.16) grown through molecular beam epitaxy (MBE) on sapphire substrates. We analyzed the surface roughness and damage using atomic force microscopy (AFM) and nano-indenter techniques. The scratched surfaces of the Zn1-xMnxO epilayers were significantly different for the various Mn compositions. AFM imaging of the Zn1-xMnxO films revealed that pileup phenomena were important on both sides of each scratch. During the scratching process, we found that cracking dominated in the case of Zn1-xMnxO films while ploughing; also we observed lower values of the coefficient of friction and shallower penetration depths for the films upon increasing the Mn content (x) from 0 to 0.16, suggesting that higher Mn contents provided the Zn1-xMnxO epilayers with higher shear resistances, enhanced by the presence of MnO bonds. (C) 2010 Elsevier Ltd. All rights reserved.
Evolution of carrier distribution and defects in InGaAsN/GaAs quantum wells with composition fluctuation
(2006-07-01)
Chen, Jenn-Fang
;
Hsiao, Ru-Shang
;
Hsieh, Pei-Chen
;
Chen, Yu-Chih
;
Wang, Jyh-Shyang
Carrier distribution and defect induction in In0.34Ga0.66As0.98N0.02/GaAs-single quantum wells grown by molecular beam epitaxy at low growth rates are investigated by frequency-dependent capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS). The C-V studies show that lowering the growth rate of the InGaAsN layer splits the carrier accumulation in the well into a central and two side peaks with different frequency dispersions. The DLTS studies show that a continuum of states (0-0.083eV) and a,deep trap at 0.21-0.25eV are responsible for the central and the side peaks, respectively. A comparison with photoluminescence (PL) spectra shows that these defects are induced by composition fluctuation. Lowering the growth rate degrades composition fluctuation by segregating the material into an InGaAsN phase and an N-depleted phase. Post-growth annealing can remove the deep trap and improve the InGaAsN emission, confirming that the deep trap degrades the InGaAsN phase. The feature of the continuum of states suggests that it may be the structural defects associated with lattice expansion or localized states introduced by composition fluctuation.
Low threshold current, low resistance 1.3 mu m InAs-InGaAs quantum-dot VCSELs with fully doped DBRs grown by MBE
(2007-01-01)
Yu, Hsin-Chieh
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Wang, Jyh-Shyang
;
Su, Yan-Kuin
;
Chang, Shoou-Jinn
;
Kuo, Hao-Chung
The processing technology of 1.3 mu m InAs-InGaAs quantum-dot VCSELs with fully doped DBRs grown by MBE will be demonstrated. The threshold currents of the fabricated devices with 10 mu m oxide-confined aperture are 0.7mA, which correspond to 890A/cm(2) threshold current density. And the threshold voltage of the device is 1.03V and maximum output power is 33 M. The series resistance is 85 Omega which is 10 times lower then our preliminary work and 3 times lower then intracavity contacted InAs-InGaAs quantum-dot VCSEL. This relatively lower resistance can even comparable with the best result reported in InGaAs oxide-confined VCSELs with intracavity contact.
Optical and Electrical Characterizations of ZnMnO Thin Films on c-Al(2)O(3)
(2009-04-01)
Lin, Hung-Ji
;
Lin, Der-Yuh
;
Wu, Jenq-Shinn
;
Yang, Chu-Shou
;
Chou, Wu-Ching
We have studied the manganese (Mn) composition dependence of the optical and electrical properties of ZnMnO thin films, which are grown on c-Al(2)O(3) substrates by plasma-assisted molecular beam epitaxy (PAMBE). The lattice constant and grain size are estimated by Xray diffraction (XRD), and it is found that the lattice constant increases and the grain size decreases with increasing Mn composition. When more Mn is incorporated into the ZnMnO thin films, a blue shift of the absorption edges and photoluminescence emission peaks are observed. Hall measurement shows n-type conduction behavior for all the samples. The decrease in mobility might be related with the increase in the number of impurity scattering centers, and the decrease in the carrier concentration can be attributed to the carrier quenching effect induced by the deep-level defects. The ac electrical response of ZnMnO is studied by impedance spectroscopy (IS). The equivalent RC circuit and parameters of the grain and grain boundary are determined. (C) 2009 The Japan Society of Applied Physics
Optical and Electrical Characterizations of ZnMnO Thin Films on c-Al2O3
(2009-04-01)
Lin, Hung-Ji
;
Lin, Der-Yuh
;
Wu, Jenq-Shinn
;
Yang, Chu-Shou
;
Chou, Wu-Ching
We have studied the manganese (Mn) composition dependence of the optical and electrical properties of ZnMnO thin films, which are grown on c-Al2O3 substrates by plasma-assisted molecular beam epitaxy (PAMBE). The lattice constant and grain size are estimated by Xray diffraction (XRD), and it is found that the lattice constant increases and the grain size decreases with increasing Mn composition. When more Mn is incorporated into the ZnMnO thin films, a blue shift of the absorption edges and photoluminescence emission peaks are observed. Hall measurement shows n-type conduction behavior for all the samples. The decrease in mobility might be related with the increase in the number of impurity scattering centers, and the decrease in the carrier concentration can be attributed to the carrier quenching effect induced by the deep-level defects. The ac electrical response of ZnMnO is studied by impedance spectroscopy (IS). The equivalent RC circuit and parameters of the grain and grain boundary are determined. (C) 2009 The Japan Society of Applied Physics
The reduction of antiphase boundary defects by the surfactant antimony and its application to the III-V multi-junction solar cells
(2016-01-01)
Tong, Shih-chang
;
Wang, Jyh-Shyang
;
Wu, Chii-Bin
;
Wu, Chih-Hung
;
Chang, Jung-Ting
The CuPtB ordering and the antiphase boundaries (APBs) in GaInP2 epifilms were found to be diminished by the addition of the surfactant antimony (Sb) during the epitaxy. This is evidenced by the disappearance of the APBs related deep level peak in the Raman and photoluminescence (PL) spectra, as well as the significantly increased lifetime of the minority carriers. The GaInP2/metamorphic (MM)-GaInAs/Ge multi-junction solar cells made by this method possess enhanced short circuit current density and show a narrower distribution of the open circuit voltage. We believe the use of surfactant Sb to control APBs during the growth of InGaP2 would be very useful for designing GaInP2-based devices, such as solar cells, laser diodes and light-emitting diodes. (C) 2015 Elsevier B.V. All rights reserved.