• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.1
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• pp.51-54
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• 2009

Transparent Cuprous oxide film was deposited by rapid thermal oxidation (RTO) of Cu at $500^{\circ}C$/45s condition on textured single-crystal n-Si substrate to form $Cu_2O$/n-Si heterojunction photodiode. The Hall effect measurements for the $Cu_2O$ films showed a p-type conductivity. The photovoltaic and electrical properties of the junction at room temperature were investigated without any post-deposition annealing. I-V characteristics revealed that the junction has good rectifying properties. The C-V data showed abrupt junction and a built-in potential of 1 V. The photodiode showed good stability and high responsivity in the visible at three regions; 525 nm, 625-700 nm, and 750nm denoted as regions A, B, and C, respectively.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.117-123
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• 2014

The fabrication and characterization of a Si/ZnO thin film heterojunction ultraviolet photodiode has been presented in this paper. ZnO thin film of ~100 nm thick was deposited on <100> Silicon (Si) wafer by atomic layer deposition (ALD) technique. The Photoluminescence spectroscopy confirms that as-deposited ZnO thin film has excellent visible-blind UV response with almost no defects in the visible region. The room temperature current-voltage characteristics of the n-ZnO thin film/p-Si photodiodes are measured under an UV illumination of $650{\mu}W$ at 365 nm in the applied voltage range of ${\pm}2V$. The current-voltage characteristics demonstrate an excellent UV photoresponse of the device in its reverse bias operation with a contrast ratio of ~ 1115 and responsivity of ~0.075 A/W at 2 V reverse bias voltage.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2613-2616
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• 2009

FeOOH/$TiO_2$, a heterojunction structure between FeOOH and $TiO_2$, was prepared by covering the surface of the $\sim$100-nm-sized FeOOH particles with Degussa P25 by applying maleic acid as an organic linker. Under visible light irradiation (${\lambda}{\geq}$ 420 nm), FeOOH/$TiO_2$ showed a notable photocatalytic activity in removal of gaseous 2-propanol and evolution of $CO_2$. It was found that FeOOH reveals a profound absorption in the spectral range of 400 - 550 nm, and its valence band (VB) level is located relatively lower than that of $TiO_2$. The considerable photocatalytic efficiency of the FeOOH/$TiO_2$ under visible light irradiation was therefore deduced to be caused by the hole transfer between the VB of FeOOH and $TiO_2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.63-66
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• 2000

In this paper, we present the simulation of the heterojunction bipolar transistor with different Emitter-Base junction structures. Our simulation results include effect of setback and graded layer. We prove the emitter efficiency's improvement through setback and graded layer. In 1995, the analytical equations of electric field, electrostatic potential, and junction capacitance for abrupt and linearly graded heterojunctions with or without a setback layer was derived. But setback layer and linearly graded layer's recombination current was considered numerically. Later, recombination current model included setback layer and graded layer will be proposed. New recombination current model also wile include abrupt heterojunction's recombination current model. In this paper, the material parameters of the heterojunction bipolar transistor with different Emitter-Base junction structures is introduced.

• Journal of the Korean GEO-environmental Society
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• v.24 no.3
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• pp.23-27
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• 2023

Graphitic carbon nitride (g-C₃N₄) has been used as effective photocatalyst for degradation of antibiotics under visible light irradiation. However, the fast recombination of hole-electron pair may limit their photocatalytic efficiency. In our study, Ag was grafted on g-C₃N₄/g-C₃N₄ isotype heterojunction by a microwave-assisted decomposition method. The structure and physical properties of heterojunction photocatalyst were characterized through X-ray diffraction, UV-DRS, FT-IR, and Photoluminescence analyses. Ag decorated g-C₃N₄/g-C₃N₄ isotype heterojunction exhibited excellent photocatalytic activity for degradation of sulfamethoxazole under irradiation under visible light irradiation within 210 min, which is higher than g-C₃N₄/g-C₃N₄ isotype heterojunction and bulk g-C₃N₄. The addition of Ag may broaden the visible light absorption and restrict the recombination of hole-electron pair because of the surface plasmons resonance, resulting in the improving the photocatalytic activity.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.520-526
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• 1994

A rectifying heterojunction consisting of polyparaphenylene(PPP) and polypyrrole(PPY) films was prepared by the electrochemical method. The photoresponse in the heterojunction of PPY and PPP is similar to the absorption spectrum of undoped PPP. This fact suggests that photoresponse depends strongly upon polyparaphenylene of semiconductor. The fill-factor was calculated from the photo current-voltage curve to be 0.19, which is relatively small compared to polyacetylene-polythiophene heterojunctions.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.431-431
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• 2008

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.432-432
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• 2008

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.560-560
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• 2006

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.49-52
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• 2002

A new method is developed to extract model parameters of SiGe HBT equivalent circuit including the base impedance and base-collector junction capacitance. Using this method, all resistances and capacitances of SiGe HBT are independently determined from measured S-parameters using two-port parameter formula. This method is proposed to reduce possible errors generated from global optimization process, and its accuracy has been verified by finding good agreements between measured and modeled current / power gain up to 18 GHz.