Ming-Chun Tseng

Universidad Nacional de Formosa, Formosa, Formosa, Argentina

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Publications (13)21.96 Total impact

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    ABSTRACT: This study reports the use of cross-shaped pattern epitaxial lift-off (ELO) technology to release crack-free single crystal epilayers with a solar cell structure from a gallium arsenide (GaAs) substrate. A cross-shaped pattern array was used to define cell size and provide the etch path for the etchant solution. AlAs was used as a sacrificial layer and etched using a hydrofluoric acid etchant through the cross-shaped hole. Results indicate that the entire wafer can be etched simultaneously. The desired carrier, i.e., the electroplate nickel substrate, can directly contact the epilayer without wax or low-viscosity epoxy, and can also be applied to an external force through magnetic attraction to decrease the release time. After the cross-shaped pattern ELO process, the separated GaAs substrate can be recycled through chemical cleaning. The performance of solar cells grown on new and recycled GaAs substrates remained above 90% of the initial performance when the substrate was recycled less than three times.
    IEEE Transactions on Electron Devices 03/2012; 59(3):666-672. · 2.06 Impact Factor
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    ABSTRACT: This article reports the quality of InxGa1−xAs (0
    Vacuum. 02/2012;
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    ABSTRACT: This paper presents the In<sub>0.17</sub>Ga<sub>0.83</sub>As solar cell grown on misoriented GaAs substrate (2°- and 15<sup>°</sup>-off) by metalorganic chemical vapor deposition. The crystalline quality of the In<sub>0.17</sub>Ga<sub>0.83</sub>As solar cell is determined by X-Ray reciprocal space mapping (RSM). RSM results show that the crystalline quality of In<sub>0.17</sub>Ga<sub>0.83</sub>As solar cell grown on 2°-off GaAs substrate is better than that of 15°-off GaAs substrate. Moreover, the photovoltaic performance of In<sub>0.17</sub>Ga<sub>0.83</sub>As solar cell grown on 2°-off GaAs substrate is found to be better than that of In<sub>0.17</sub>Ga<sub>0.83</sub>As solar cell grown on a 15°-off GaAs substrate, because the In<sub>x</sub>Ga<sub>1-x</sub>As epilayer grown on 15°-off GaAs substrate shows a large strain relaxation in the active layer of the solar cell. A large strain relaxation causes high dislocation density at the initial active layer/In<sub>x</sub>Ga<sub>1-x</sub>As graded layer interface for the solar cell grown on 15°-off GaAs substrate. The effect of dislocation defects on the solar cell performance can be alleviated using the p-i-n structure as the epilayer grown on 15°-off GaAs substrate.
    IEEE Journal of Quantum Electronics 12/2011; · 2.11 Impact Factor
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    ABSTRACT: This paper presents the thermal effect on the performance of a GaAs thin-film solar cell with a 50-200- μm-thick copper (Cu) substrate. The GaAs thin-film solar cell is fabricated by transferring a GaAs solar cell on a Cu substrate with a AuGe/Au mirror. The thin-film solar cells with sufficiently thick Cu substrates exhibit significant performance stability (e.g., V <sub>oc</sub>, J <sub>sc</sub>, and FF ) as the temperature increases. This stability can be attributed to the following two factors: 1) The highly reflective AuGe/Au mirror enhances the light absorption of the thin-film cell with a thin base layer, and 2) the good thermal dissipation of the Cu substrate reduces thermal degradation.
    IEEE Transactions on Electron Devices 12/2011; · 2.06 Impact Factor
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    ABSTRACT: Abstract
    01/2011;
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    ABSTRACT: In<sub>0.16</sub>Ga<sub>0.84</sub>As solar cells grown on GaAs substrates with different miscut angles via metalorganic chemical vapor deposition were utilized to study the effect of substrate orientation on solar cell efficiency. A p-n In<sub>0.16</sub>Ga<sub>0.84</sub>As solar cell grown on a 2°-off GaAs substrate exhibited better conversion efficiency than one grown on a 15°-off GaAs substrate. The poor performance of the 15°-off In<sub>0.16</sub>Ga<sub>0.84</sub>As solar cell could be attributed to the formation of high-density misfit dislocations through strain relaxation, thereby reducing the minority carrier lifetime. The conversion efficiency of a 15°-off In<sub>0.16</sub>Ga<sub>0.84</sub>As solar cell was improved using a p-i-n structure. Using the p-i-n structure design, a 15°-off In<sub>0.16</sub>Ga<sub>0.84</sub>As solar cell showed conversion efficiency close to or even better than that of a 2°-off In<sub>0.16</sub>Ga<sub>0.84</sub>As solar cell with the same structure.
    IEEE Transactions on Electron Devices 10/2010; · 2.06 Impact Factor
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    ABSTRACT: This paper presents the quality of InxGa1−xAs (0
    Thin Solid Films 01/2010; 518(24):7213-7217. · 1.87 Impact Factor
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    ABSTRACT: This letter presents performance comparison between a GaAs/mirror/copper thin-film solar cell and a conventional GaAs solar cell with a thick GaAs substrate. The GaAs thin-film solar cell was fabricated by transferring a GaAs solar cell onto a AuGe/Au mirror-coated copper substrate. With the aid of the excellent copper conductor, the thin-film solar cell exhibits significant improvement in both open-circuit voltage and short-circuit current density. The improved current-voltage ( I - V ) performance of the thin-film solar cell originates from the following two factors: reduced reverse saturation current by good heat dissipation of copper and enhanced light absorption by the highly reflective AuGe/Au mirror. The role of the mirror can further be verified in the measurement of external quantum efficiency (EQE) response where the thin-film solar cell exhibits a larger EQE response in the wavelength range of 700-900 nm than the conventional GaAs solar cell with the same active absorbing thickness.
    IEEE Electron Device Letters 10/2009; · 2.79 Impact Factor
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    ABSTRACT: In-rich and Ga-rich GaInP films were intentionally grown on (001) GaAs substrates by low-pressure MOCVD to investigate the effect of lattice strain on composition. High-resolution X-ray diffraction (HRXRD) measurement showed that a GaInP single layer exhibits a double-diffracted peak phenomenon. Such a double peak represents a composition separation in the grown film, resulting in two absorption cutoff energies in optical absorption analysis. Cross-sectional transmission electron microscopic (TEM) observation confirmed the composition separation in an In-rich GaInP film. Furthermore, the composition separation amount of a Ga-rich GaInP film after substrate removal was found to be ∼0.5%, which reflects the actual effect of lattice strain on composition during growth stage.
    Journal of Crystal Growth 01/2009; 311(11):3220-3224. · 1.55 Impact Factor
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    ABSTRACT: In this paper, we report on the influence of compositionally step-graded Ga1-xInxP multilayers on the microstructural and optical properties of In-rich Ga0.46In0.54P film grown on a GaAs substrate. Based on the transmission electron microscope observation, the growth of Ga0.46In0.54P on GaAs was found to result in phase separation, which was due to the strain-induced composition pulling effect. This phase separation could be successfully eliminated by the step-graded Ga1-xInxP multilayers with optimized thickness. The elimination was caused by the sufficient moderation of compressive strain in the subsequently grown Ga0.46In0.54P film. The employment of step-graded Ga1-xInxP multilayers was also helpful in improving compositional uniformity and photoluminescence property of the subsequently grown film. The compositional dependence of the film structure and the ab initio elastic constants were used to show that Ga1-xInxP multilayers with a systematic increase in the In-rich compositional regime exhibit epitaxial stability.
    Journal of Applied Physics 01/2009; 106. · 2.21 Impact Factor
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    ABSTRACT: Cyclic olefin copolymer (COC) substrate surface was modified by plasma treatment under oxygen atmosphere. The surface properties were evaluated by contact angle measurement, atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). It was found that the surface acquired oxygen containing polar functional groups such as C–O, C=O, which increased in number as the plasma treatment time increased. As revealed by AFM profile, these changes were accompanied by a slightly increase in roughness. The adhesive ability between the coating layer (ITO) and the COC surface can be improved after optimum plasma treating procedure, which can be proofed by the optical microscope observation after boiling test.
    Surface and Coatings Technology 01/2008; 202(15):3669-3674. · 1.94 Impact Factor
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    ABSTRACT: Phosphorous-doped microcrystalline silicon (μc-Si) films were prepared using hot-wire chemical vapor deposition (HWCVD). Structural, electrical and optical properties of these thin films were systematically studied as a function of PH3 gas mixture ratio. We report recent results for p-type crystalline silicon-based heterojunction (HJ) solar cells using the HWCVD n-μc-Si film to form an n–p junction. The surface morphology of the crystalline Si substrate after hydrogen treatment was examined using atomic force microscopy. A transfer length method was used to modify the indium–tin–oxide (ITO) deposition parameters in order to reduce front ITO/n-μc-Si contact resistance. In our best solar cell sample (1 cm2) without any buffer layer, the conversion efficiency of 15.1% has been achieved with an open circuit voltage of 0.615 V, fill factor of 0.71 and short circuit current density of 34.6 mA/cm2 under 100 mW/cm2 condition. The spectral response of this cell will also be discussed.
    Thin Solid Films 01/2008; 516(5):765-769. · 1.87 Impact Factor
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    ABSTRACT: Indium tin oxide (ITO) thin films were deposited on cyclic olefin copolymer substrate at room temperature by an inverse target sputtering system. The crystal structure and the surface morphology of the deposited ITO films were examined by X-ray diffraction and atomic force microscopy, separately. The electrical properties of the conductive films were explored by four-point probing. Visible spectrometer was used to measure the optical properties of ITO-coated films. The performance of the flexible organic light emitting diode device with different thickness anode was investigated in this study.
    Optics Communications 01/2006; 259(1):187-193. · 1.44 Impact Factor

Publication Stats

22 Citations
21.96 Total Impact Points

Institutions

  • 2006–2012
    • Universidad Nacional de Formosa
      Formosa, Formosa, Argentina
  • 2011
    • National Cheng Kung University
      • Department of Electrical Engineering
      臺南市, Taiwan, Taiwan
  • 2008
    • National Chung Hsing University
      • Department of Materials Science and Engineering
      Taichung, Taiwan, Taiwan