Browsing by Author "Hong Quan Nguyen"

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Band Alignment Parameters of Al2O3/InSb Metal-Oxide-Semiconductor Structure and Their Modification with Oxide Deposition Temperatures
(2013-06-01)
Hai Dang Trinh
;
Minh Thuy Nguyen
;
Lin, Yueh Chin
;
Quoc Van Duong
;
Hong Quan Nguyen
From the Fowler-Nordheim (FN) current-voltage (I-V) characteristic and X-ray photoelectron spectroscopy (XPS) analysis, the conduction band offset of 2.73 +/- 0.1 eV and the valence band offset of 3.76 +/- 0.1 eV have been extracted for the atomic-layer-deposition (ALD) Al2O3/InSb structure. By these analyses, the parameters of an Al2O3 film including bandgap, electron affinity, and electron effective mass are also deduced. The capacitance-voltage and I-V characteristics of ALD Al2O3/InSb at different deposition temperatures indicate the modification of the Fermi level in InSb to 0.09 eV lower than that in metal side of the sample deposited at 250 degrees C as compared to the samples deposited at lower temperatures. (C) 2013 The Japan Society of Applied Physics
C-V characteristics of epitaxial germanium metal-oxide-semiconductor capacitor on GaAs substrate with ALD Al2O3 dielectric
(2012-09-01)
Tang, Shih Hsuan
;
Kuo, Chien I.
;
Hai Dang Trinh
;
Hudait, Mantu
;
Chang, Edward Yi
Epitaxial germanium metal-oxide-semiconductor capacitors (MOSCAP) were fabricated on GaAs substrate using atomic layer deposited Al2O3 gate dielectric with surface treatments including pure HF and HF plus rapid thermal oxidation (RTO). The electrical characteristics of 10 nm Al2O3/Ge MOSCAP showed p-type behavior with excellent C-V responses and low leakage current. Interface state density in the order of 10(11) eV(-1) cm(-2) was determined from the conductance method and the HF plus RTO treatment exhibits better Al2O3/Ge interface quality than that of pure HF treatment. (C) 2012 Elsevier B.V. All rights reserved.
Electrical Characteristics of Al2O3/InSb MOSCAPs and the Effect of Postdeposition Annealing Temperatures
(2013-05-01)
Hai Dang Trinh
;
Lin, Yueh Chin
;
Chang, Edward Yi
;
Lee, Ching-Ting
;
Wang, Shin-Yuan
The characteristics of Al2O3/InSb MOSCAPs processed with different postdeposition annealing (PDA) temperatures are investigated. X-ray photoelectron spectroscopy analysis shows a significant reduction of InSb-oxides after HCl plus trimethyl aluminum treatment and oxide deposition. Multifrequency capacitance-voltage (C-V) characteristics exhibit low-frequency and asymmetrical C-V behaviors, in which capacitance in the InSb conduction band side is lower than in the valence band side. The electrical properties of the MOSCAPs are sensitive to PDA temperature and degraded significantly at PDA temperature > 300 degrees C. This degradation is closely related to the diffusion of In, Sb into Al2O3 as indicated by transmission electron microscopy analyses.
Electrical Characteristics of n, p-In0.53Ga0.47As MOSCAPs With In Situ PEALD-AlN Interfacial Passivation Layer
(2014-08-01)
Quang Ho Luc
;
Chang, Edward Yi
;
Hai Dang Trinh
;
Lin, Yueh Chin
;
Hong Quan Nguyen
The effects of plasma enhanced atomic layer deposition (PEALD)-AlN interfacial passivation layer (IPL) on the Al2O3/In0.53Ga0.47As interfaces qualities are studied with different plasma powers. The improvement in electrical properties, including capacitance-voltage (C-V) hysteresis, frequency dispersion, and interface state densities (D-it) are demonstrated on the Al2O3/n, p-In0.53Ga0.47As MOS capacitors. The excellent C-V behaviors are observed on both type of In0.53Ga0.47As-based MOS devices by performing a thin AlN-IPL at the plasma power of 150 W. To explore the interaction between PEALD-AlN layer and In0.53Ga0.47As surface, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analyses have also been characterized.
Gold-Free Fully Cu-Metallized InGaP/InGaAs/Ge Triple-Junction Solar Cells
(2014-12-01)
Hsu, Ching-Hsiang
;
Chang, Edward Yi
;
Chang, Hsun-Jui
;
Yu, Hung-Wei
;
Hong Quan Nguyen
Copper contacts and interconnects were developed for GaAs and Ge for low-cost solar cell application. In addition, thermally annealed Pd/Ge and Pt/Ti/Pt metallizations were created for ohmic contacts to n-GaAs and p-Ge with contact resistance of 4.4 x 10(-6) and 6.9 x 10(-6) Omega cm(2), respectively. Utilizing such metallization structure for InGaP/InGaAs/Ge triple-junction device structure solar cells were fabricated that delivered conversion efficiency of 23.11%, which is average efficiency for the above device structure.
High-Quality 1 eV In(0.3)Ga(0.7)As on GaAs Substrate by Metalorganic Chemical Vapor Deposition for Inverted Metamorphic Solar Cell Application
(2011-07-01)
Hong Quan Nguyen
;
Chang, Edward Yi
;
Yu, Hung Wei
;
Lin, Kung Liang
;
Chung, Chen Chen
In(0.3)Ga(0.7)As layers were grown by metalorganic chemical vapor deposition using step graded buffer layers on different misoriented GaAs(001) substrates. Smooth-surface In(0.3)Ga(0.7)As film with a root mean square roughness of 1.9 nm was obtained with the growth temperature of 490 degrees C using a 10-step graded parabolic-like indium profile buffer layer on the surface with the 6 degrees-off cut toward the [111] direction. The threading dislocation density in the film was determined to be 1.2 x 10(6) cm(-2) by transmission electron microscopy. The photoluminescence results obtained at 300 and 77K indicate that very low recombination centers existed in the epilayer. (C) 2011 The Japan Society of Applied Physics
High-Quality 1 eV In0.3Ga0.7As on GaAs Substrate by Metalorganic Chemical Vapor Deposition for Inverted Metamorphic Solar Cell Application
(2011-07-01)
Hong Quan Nguyen
;
Chang, Edward Yi
;
Yu, Hung Wei
;
Lin, Kung Liang
;
Chung, Chen Chen
In0.3Ga0.7As layers were grown by metalorganic chemical vapor deposition using step graded buffer layers on different misoriented GaAs(001) substrates. Smooth-surface In0.3Ga0.7As film with a root mean square roughness of 1.9 nm was obtained with the growth temperature of 490 degrees C using a 10-step graded parabolic-like indium profile buffer layer on the surface with the 6 degrees-off cut toward the [111] direction. The threading dislocation density in the film was determined to be 1.2 x 10(6) cm(-2) by transmission electron microscopy. The photoluminescence results obtained at 300 and 77K indicate that very low recombination centers existed in the epilayer. (C) 2011 The Japan Society of Applied Physics
InGaP/GaAs Dual-Junction Solar Cell with AlGaAs/GaAs Tunnel Diode Grown on 10 degrees off Misoriented GaAs Substrate
(2012-08-01)
Yu, Hung Wei
;
Chung, Chen Chen
;
Wang, Chin Te
;
Hong Quan Nguyen
;
Binh Tinh Tran
InGaP/GaAs dual-junction solar cells with different tunnel diodes (TDs) grown on misoriented GaAs substrates are investigated. It is demonstrated that the solar cells with P++-AlGaAs/N++-GaAs TDs grown on 10 degrees off GaAs substrates not only show a higher external quantum efficiency (EQE) but also generate a higher peak current density (J(peak)) at higher concentration ratios (185 x) than the solar cells with P++-GaAs/N++-InGaP TDs grown on 6 degrees off GaAs substrates. Furthermore, the cell design with P++-AlGaAs/N++-GaAs TDs grown on 10 degrees off GaAs substrates does not generate a disordered InGaP epitaxial layer during material growth, and thus shows superior current-voltage characteristics. (c) 2012 The Japan Society of Applied Physics
Porous (001)-faceted Zn-doped anatase TiO2 nanowalls and their heterogeneous photocatalytic characterization
(2014-01-01)
Saad, Siti Khatijah Md
;
Umar, Akrajas Ali
;
Hong Quan Nguyen
;
Dee, Chang Fu
;
Salleh, Muhamad Mat
The synthesis of a poriferous and high energy (001) faceted anatase Zn-doped TiO2 nanowall (ZnTNW), vertically grown on an indium tin oxide substrate, is presented. The ZnTNW was prepared using a modified liquid phase deposition method using zinc nitrate (Zn(NO3)(2)center dot xH(2)O) as a fluoride scavenger in the presence of hexamethylenetetramine. In a typical procedure, the ZnTNW nanowall with length and thickness of approximately 2 mu m and 60 nm, respectively, can be obtained from the reaction during a 5 h growth process. X-ray diffraction analysis shows that the nanowall has an anatase structure with a dominant high energy (001) basal plane. Meanwhile, the X-ray energy dispersive analysis confirms the presence of Zn in the TiO2 nanowall. High resolution transmission electron microscopy analysis results reveal, surprisingly, that the ZnTNW is single crystalline in nature although it has a highly porous (surface and bulk) structure. Photocatalytic properties of the ZnTNW were examined in the degradation of methylene blue. It was found that the ZnTNW exhibits excellent photocatalytic efficiency with kinetic reaction rate, turnover number and turnover frequency as high as 0.004 min(-1), 760 and 11 min(-1), respectively. The photocatalytic performance of the ZnTW was found to be higher for about 10% and 50% than the pristine TiO2 nanowalls and (001) faceted poriferous TiO2 microtablet, which reflected the effective effect of the Zn doping. The ZnTNW may find potentially use in photocatalytic heterogeneous applications.
The Growth and Fabrication of High-Performance In0.5Ga0.5As Metal-Oxide-Semiconductor Capacitor on GaAs Substrate by Metalorganic Chemical Vapor Deposition Method.
(2012-01-01)
Hong Quan Nguyen
;
Hai Dang Trinh
;
Yu, Hung Wei
;
Hsu, Ching Hsiang
;
Chung, Chen Chen
Growth conditions have investigated for growing high quality In0.3Ga0.7As and In0.5Ga0.5As on GaAs substrate by metalorganic chemical vapor deposition method. Annihilation reactions between threading dislocations observed by transmission electron microscopy are experimental evidences to confirm threading dislocations had been blocked in InxGa1-xAs buffer layers. A high quality smooth surface In0.5Ga0.5As epi-film with threading dislocation density of 2x10(6) cm(-2) was achieved at growth temperature of 490 degrees C. Metal-oxide-semiconductor capacitor devices fabricated on In0.5Ga0.5As/GaAs perform nice capacitance-voltage response, with small frequency dispersion. The conductance contours indicate that the Fermi level moves freely to the lower part of the InGaAs bandgap without pinning.